Class 10 Exam  >  Class 10 Notes  >  Extra Documents, Videos & Tests for Class 10  >  Co­ordinate Geometry Exercise 14.1 (Part-13)

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 PDF Download

Question 8: Find the area of the triangle PQR with Q(3, 2) and the mid-points of the sides through Q being (2, −1) and (1, 2). 

Answer : Let P(x1y1), Q(3, 2) and R(x2y2) be the vertices of the ∆PQR.
Suppose S(2, −1) and T(1, 2) be the mid-points of sides QR and PQ, respectively.

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Using mid-point formula, we have 

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

⇒x1=−1, y1=2 

Coordinates of P = (−1, 2) 

Also,

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Coordinates of R = (1, −4) 

So, P(−1, 2), Q(3, 2) and R(1, −4) are the vertices of ∆PQR. 

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

 =12 square units 

Hence, the area of the triangle is 12 square units. 

Question 9: If P(−5, −3), Q(−4, −6), R(2, −3) and S(1, 2) are the vertices of a quadrilateral PQRS, find its area.  

Answer : It is given that P(−5, −3), Q(−4, −6), R(2, −3) and S(1, 2) are the vertices of a quadrilateral PQRS.

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Area of the quadrilateral PQRS = Area of ∆PQR + Area of ∆PRS 


Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

=1/2|5[6(3)]+(4)[3(3)]+2[3(6)]| 

=1/2|15+0+6| 

21/2 square units 

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

= 35/2 square units 

∴ Area of the quadrilateral PQRS = Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 square units 

Hence, the area of the given quarilateral is 28 square units. 

Question 10: If A(−3, 5), B(−2, −7), C(1, −8) and D(6, 3) are the vertices of a quadrilateral ABCD, find its area.

Answer : It is given that A(−3, 5), B(−2, −7), C(1, −8) and D(6, 3) are the vertices of a quadrilateral ABCD. 

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10
Area of the quadrilateral ABCD = Area of ∆ABC + Area of ∆ACD

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 

=1/2 
|
3[7(8)]+(2)(85)+1[5(7)]| 

=1/2|3+26+12| 

=35/2 square units 

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

=1/2|3(83)+1(35)+6[5(8)]| 

=1/2|332+78| 

= 109/2 square units 

∴ Area of the quadrilateral ABCD = Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 1072352+1092=1442=72 square units 

Hence, the area of the given quadrilateral is 72 square units. 

Question 11: For what value of a the point (a, 1), (1, −1), and (11, 4) are collinear?

Answer : The formula for the area ‘A’ encompassed by three pointsCo­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 and Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 is given by the formula, 

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

If three points are collinear the area encompassed by them is equal to 0.

The three given points are A(a, 1), B(1, −1) and C(11, 4). It is also said that they are collinear and hence the area enclosed by them should be 0.

Δ=1/2 |(x1y2+x2y3+x3y1)(x2y1+x3y2+x1y3)| 

 0=1/2 |(a×1+1×4+11×1)(1×1+11×1+a×4)| 

 0=1/2 | (a+4+11)(111+4a)| 

 0=1/2|(a+15)(10+4a)| 

 0=1/2|a+15+104a| 

  0=1/2|5a+25| 

 0=−5a+25

5a=25   

a=5 

Hence the value of ‘a’ for which the given points are collinear isCo­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10. 

Question 12:Prove that the points (a, b), (a1, b1) and (a −a1, b −b1) are collinear if ab1 = a1b.

Answer : The formula for the area ‘A’ encompassed by three pointsCo­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 and Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 is given by the formula, 

Δ=1/2|(x1y2+x2y3+x3y1)(x2y1+x3y2+x1y3)|∆=12x1y2+x2y3+x3y1-x2y1+x3y2+x1y3 

If three points are collinear the area encompassed by them is equal to 0.

The three given points areCo­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10,Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 andCo­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10. If they are collinear then the area enclosed by them should be 0.

Δ=1/2|(ab1+a1(bb1)+(aa1)b)(a1b+(aa1)b1+a(bb1))| 

0=1/2|(ab1+a1ba1b1+aba1b)(a1b+ab1a1b1+abab1)| 

 0=1/2|ab1+a1ba1b1+aba1ba1bab1+a1b1ab+ab1| 

 0=ab1a1b 

ab1=a1b 

Hence we have proved that for the given conditions to be satisfied we need to haveCo­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10. 

Question 13: If the vertices of a triangle are (1, −3), (4, p) and (−9, 7) and its area is 15 sq. units, find the value(s) of p.     

Answer : Let A(1, −3), B(4, p) and C(−9, 7) be the vertices of the ∆ABC.
Here, x1 = 1, y1 = −3; x2 = 4, y2 = and x3 = −9, y3 = 7
ar(∆ABC) = 15 square units

1/2|x1(y2y3)+x2(y3y1)+x3(y1y2)|=151/2|1(p7)+4[7(3)]+(9)(3p)|=151/2|p7+40+27+9p|=15|10p+60|=30

10p+60=30⇒10p+60=30 or 10p+60=3010p+60=-30
10p=30⇒10p=-30 or 10p=9010p=-90
p=3⇒p=-3 or p=9p=-9
Hence, the value of is −3 or −9. 

Question 14: If (x, y) be on the line joining the two points (1, −3) and (−4, 2) , prove that x + y + 2= 0.

Answer : Since the point (x, y) lie on the line joining the points (1, −3) and (−4, 2); the area of triangle formed by these points is 0.

That is,

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Thus, the result is proved.

Question 15: Find the value of k if points A(k, 3), B(6, −2) and C(−3, 4) are collinear.

Answer : The formula for the area ‘A’ encompassed by three pointsCo­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 and Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 is given by the formula, 

Δ=1/2|(x1y2+x2y3+x3y1)(x2y1+x3y2+x1y3)|∆=12x1y2+x2y3+x3y1-x2y1+x3y2+x1y3 

If three points are collinear the area encompassed by them is equal to 0.

The three given points are A(k, 3), B(6, −2) and C(3, 4). It is also said that they are collinear and hence the area enclosed by them should be 0.

Δ=1/2|(k(2)+6×4+(3)×3)(6×3+(3)(2)+k×4)| 0=1/2|(2k+249)(18+6+4k)| 0=1/2|2k+15244k| 0=1/2|6k9| 0=6k9 k=9/6 =−3/2

Hence the value of ‘k’ for which the given points are collinear isCo­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10. 

Question 16: Find the value of k, if the points A(7, −2), B (5, 1) and (3, 2k) are collinear.

Answer : The formula for the area ‘A’ encompassed by three pointsCo­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10, Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 and Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 is given by the formula,

Δ=1/2|(x1y2+x2y3+x3y1)(x2y1+x3y2+x1y3)|∆=12x1y2+x2y3+x3y1-x2y1+x3y2+x1y3

If three points are collinear the area encompassed by them is equal to 0.

The three given points are A(7, −2), B(5, 1) and C(3, 2k). It is also said that they are collinear and hence the area enclosed by them should be 0.

Δ=1/2|(7×1+5×2k+3×2)(5×2+3×1+7×2k)| 0=1/2|(7+10k6)(10+3+14k)| 0=1/2|4k+8| 0=4k+8 k=2∆=127×1+5×2k+3×-2-5×-2+3×1+7×2k 0=127+10k-6--10+3+14k 0=12-4k+8 0=-4k+8 k=2

Hence the value of ‘k’ for which the given points are collinear isCo­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10.

Question 17: If the point P (m, 3) lies on the line segment joining the points A(2/5,6) A-25,6 and B (2, 8), find the value of m.

Answer : The formula for the area ‘A’ encompassed by three pointsCo­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 and Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 is given by the formula, 

Δ=1/2|(x1y2+x2y3+x3y1)(x2y1+x3y2+x1y3)|∆=12x1y2+x2y3+x3y1-x2y1+x3y2+x1y3

If three points are collinear the area encompassed by them is equal to 0.

It is said that the point P(m,3) lies on the line segment joining the points Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 and B(2,8). Hence we understand that these three points are collinear. So the area enclosed by them should be 0.

 Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

0=2m+8 m=4

Hence the value of ‘m’ for which the given condition is satisfied isCo­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10. 

Question 18: If R (x, y) is a point on the line segment joining the points P (a, b) and Q (b, a), then prove that + y = a + b.

Answer : The formula for the area ‘A’ encompassed by three pointsCo­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10, Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 and Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 is given by the formula,

Δ=1/2|(x1y2+x2y3+x3y1)(x2y1+x3y2+x1y3)|∆=12x1y2+x2y3+x3y1-x2y1+x3y2+x1y3

If three points are collinear the area encompassed by them is equal to 0.

It is said that the point R(x, y) lies on the line segment joining the points P(a, b) and Q(b, a). Hence we understand that these three points are collinear. So the area enclosed by them should be 0.

 Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

 0=ay+xa+b2xbbya2 a2b2=ax+aybxby (a+b)(ab)=(ab)(x+y) (a+b)=(x+y)

Hence under the given conditions we have proved thatCo­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10. 

Question 19: Find the value of k, if the points A (8, 1) B(3, −4) and C(2, k) are collinear.

Answer : The formula for the area ‘A’ encompassed by three pointsCo­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10, Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 and Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 is given by the formula,

Δ=1/2|(x1y2+x2y3+x3y1)(x2y1+x3y2+x1y3)|∆=12x1y2+x2y3+x3y1-x2y1+x3y2+x1y3

If three points are collinear the area encompassed by them is equal to 0.

The three given points are A(8,1), B(3,4) and C(2,k). It is also said that they are collinear and hence the area enclosed by them should be 0.

Δ=1/2|(8×4+3×k+2×1)(3×1+2×4+8×k)| 0=1/2|(32+3k+2)(38+8k)| 0=1/2|255k|k=5 

Hence the value of ‘k’ for which the given points are collinear isCo­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10. 

Question 20:Find the value of a for which the area of the triangle formed by the points A(a, 2a), B(−2, 6) and C(3, 1) is 10 square units.

Answer : The formula for the area ‘A’ encompassed by three pointsCo­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 and Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 is given by the formula, 

Δ=1/2|(x1y2+x2y3+x3y1)(x2y1+x3y2+x1y3)|∆=12x1y2+x2y3+x3y1-x2y1+x3y2+x1y3 

The three given points are A(a,2a), B(2,6) and C(3,1). It is also said that the area enclosed by them is 10 square units. Substituting these values in the above mentioned formula we have, 

Δ=1/2|(a×6+(2)×1+3×2a)((2)×2a+3×6+a×1)|10=1/2|(6a2+6a)(4a+18+a)|10=1/2|15a20|20=|15a20|4=|3a4|∆=12a×6+-2×1+3×2a--2×2a+3×6+a×110=126a-2+6a--4a+18+a10=1215a-2020=15a-204=3a-4

We haveCo­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10. Hence either

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Or

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Hence the values of ‘a’ which satisfies the given conditions areCo­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10.

Question 21: Prove that the points (a, 0), (0, b) and (1, 1) are collinear if Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10=11a+1b=1.

Answer : The formula for the area ‘A’ encompassed by three pointsCo­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10, Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 and Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 is given by the formula,

We know area of triangle formed by three points Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10is given by

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

If three points are collinear the area encompassed by them is equal to 0.

The three given points are A(a,0), B(0,b) and C(1,1).

A =1/2|a(b1)+1(0b)|=1/2|abab|A = 12a(b-1)+1(0-b)=12ab-a-b

It is given that Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

So we have,

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Using this in the previously arrived equation for area we have,

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Since the area enclosed by the three points is equal to 0, the three points need to beCo­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10.

Question 22: The point A divides the join of P (−5, 1)  and Q(3, 5) in the ratio k:1. Find the two values of k for which the area of ΔABC where B is (1, 5) and C(7, −2) is equal to 2 units.

Answer : GIVEN: point A divides the line segment joining P (−5, 1) and Q (3, −5) in the ratio k: 1

Coordinates of point B (1, 5) and C (7, −2)

TO FIND: The value of k

PROOF: point A divides the line segment joining P (−5, 1) and Q (3, −5) in the ratio k: 1

So the coordinates of A are Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

We know area of triangle formed by three points Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10is given by Δ=12|(x1y2+x2y3+x3y1)(x2y1+x3y2+x1y3)|∆=12x1y2+x2y3+x3y1-x2y1+x3y2+x1y3

Now Area of ΔABC= 2 sq units.

Taking three points A Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 , B (1, 5) and C (7, −2)

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Hence Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Question 23: The area of a triangle is 5. Two of its vertices are (2, 1) and (3, −2). The third vertex lies on y = x + 3. Find the third vertex.

Answer : GIVEN: The area of triangle is 5.Two of its vertices are (2, 1) and (3, −2). The third vertex lies on y= x+3

TO FIND: The third vertex.

PROOF: Let the third vertex be (x, y)

We know area of triangle formed by three points Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10is given by Δ=12|(x1y2+x2y3+x3y1)(x2y1+x3y2+x1y3)|∆=12x1y2+x2y3+x3y1-x2y1+x3y2+x1y3

Now

Taking three points(x, y), (2, 1) and (3, −2)

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Also it is given the third vertex lies on y = x+3

Substituting the value in equation (1) and (2) we get

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Hence the coordinates of Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10and Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Question 24: If Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10, prove that the points (a, a2), (b, b2), (c, c2) can never be collinear.

Answer : GIVEN: If Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

TO PROVE: that the points Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10can never be collinear.

PROOF:

We know three points Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10are collinear when Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Now taking three pointsCo­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Also it is given that

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Hence area of triangle made by these points is never zero. Hence given points are never collinear.

Question 25: Four points A (6, 3), B (−3, 5), C(4, −2) and D (x, 3x) are given in such a way that Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 find x. 

Answer : GIVEN: four points A (6, 3), B (−3, 5) C (4, −2) and D(x, 3x) such that Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

TO FIND: the value of x

PROOF:

We know area of the triangles formed by three points Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 is given by Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Now

Area of triangle DBC taking D(x, 3x), B (−3, 5), C (4, −2)

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Area of triangle ABC taking, A (6, 3), B (−3, 5), C (4, −2)

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Also it is given that

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Substituting the values from (1) and (2) we get

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Question 26: If three points (x1, y1) (x2, y2), (x3, y3) lie on the same line, prove that Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Answer : GIVEN: If three points Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 lie on the same line

TO PROVE: Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

PROOF:

We know that three points Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 are collinear if

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10

Hence proved.

⇒12x1y2-y3+x2y3-y1+x3y1-y2=15⇒121p-7+47--3+-9-3-p=15⇒12p-7+40+27+9p=15⇒1

The document Co­ordinate Geometry Exercise 14.1 (Part-13) | Extra Documents, Videos & Tests for Class 10 is a part of the Class 10 Course Extra Documents, Videos & Tests for Class 10.
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