The document RD Sharma Solutions Ex-7.1, Introduction To Euclid's Geometry, Class 9, Maths Class 9 Notes | EduRev is a part of the Class 9 Course RD Sharma Solutions for Class 9 Mathematics.

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**Q. 1. Define the following terms.**

**(i) Line segment **

**(ii) Collinear points **

**(iii) Parallel lines **

**(iv) Intersecting lines**

**(v) Concurrent lines**

**(vi) Ray**

**(vii) Half-line**

**Solution**

(i) __Line-segment__:

Give two points A and B on a line I. the connected part (segment) of the line with end points at A and B is called the line segment AB.

(ii) __Collinear points__:

Three or more points are said to be collinear if there is a line which contains all of them.

(iii) __Parallel lines__:

Two lines l and m in a plane are said to be parallel lines if they do not intersect each other.

(iv) __Intersecting lines__:

Two lines are intersecting if they have a common point. The common point is called point of intersection.

(v) __Concurrent lines__:

Three or more lines are said to be concurrent if there is a point which lies on all of them.

(vi) __Ray__:

A line in which one end point is fixed and the other part can be extended endlessly.

(vii) __Half-line__:

If A, B. C be the points on a line l, such that A lies between B and C, and we delete the point A from line l, the two parts of l that remain are each called half-line.

**Q. 2. (i) How many lines can pan through a given point?**

**(ii) In how many points can two distinct lines at the most intersect?**

**Solution**

(i) Infinitely many

(ii) One

**Q. 3. (i) Given two points P and Q. Find how many line segments do they determine.**

**(ii) Name the line segments determined by the three collinear points P. Q and R.**

**Solution**

(i) One

(ii) PQ, QR, PR

* *

**Q. 4. Write the truth value (T/F) of each of the following statements:**

*(i) Two lines intersect in a point.*

*(ii) Two lines may intersect in two points*

*(iii) A segment has no length.*

*(iv) Two distinct points always determine a line.*

*(v) Every ray has a finite length.*

*(vi) A ray has one end-point only.*

*(vii) A segment has one end-point only.*

*(viii) The ray AB is same as ray BA.*

*(ix) Only a single line may pass through a given point.*

*(x) Two lines are coincident if they have only one point in common*

**Solution**

(i) False

(ii) False

(iii) False

(iv) True

(v) False

(vi) True

(vii) False

(viii) False

(ix) False

(x) False

**Q. 5. In the below figure. Name the following:**

* *

**Solution:**

(i) Five line segments AB, CD, AC, PQ. DS

(ii) Five rays â†’PA,â†’RB,â†’DC,â†’QS,â†’DS

(iii) Four collinear points. C, D, Q, S

(iv) Two pairs of nonâ€“intersecting line segments AB and CD, AB and LS.

**Q. 6. Fill in the blanks so as to make the following statements true:**

**(i) Two distinct points in a plane determine a _____________ line.**

**(ii) Two distinct ___________ in a plane cannot have more than one point in common.**

**(iii) Given a line and a point, not on the line, there is one and only _____________ line which passes through the given point and is _______________ to the given line.**

**(iv) A line separates a plane into _________ parts namely the __________ and the _____ itself.**

**Solution**

(i) Unique

(ii) Lines

(iii) Perpendicular, perpendicular

(iv) Three, two half planes, line.