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All questions of Mensuration: Volume, Surface Area & Solid Figures for DSSSB TGT/PGT/PRT Exam

Find the volume of a cuboid whose length is 8 cm, width is 3 cm and height is 5 cm. 
  • a)
    135 cm3
  • b)
    125 cm3
  • c)
    120 cm3
  • d)
    130 cm3
Correct answer is option 'C'. Can you explain this answer?

Tanishq Joshi answered
Finding Volume of a Cuboid

Given: length = 8 cm, width = 3 cm, height = 5 cm

To find: Volume of the cuboid

Formula: Volume of a cuboid = length x width x height

Substituting the given values in the formula, we get:

Volume = 8 cm x 3 cm x 5 cm

Volume = 120 cm3

Therefore, the correct answer is option C, 120 cm3.

Practice Quiz or MCQ (Multiple Choice Questions) with solutions are available for Practice, which would help you prepare for chapter Mensuration, Class 8, Mathematics . You can practice these practice quizzes as per your speed and improvise the topic. 
Q.
Find the volume of a cuboid whose length is 8 cm, breadth 6 cm and height 3.5 cm. 
  • a)
    215 cm3
  • b)
    172 cm3
  • c)
    150 cm3
  • d)
    168 cm3
Correct answer is option 'D'. Can you explain this answer?

Ankita Shah answered
Given,
Length (l) = 8 cm
Breadth (b) = 6 cm
Height (h) = 3.5 cm

We know that the volume of a cuboid is given by the formula:
Volume = length × breadth × height

Substituting the given values, we get:
Volume = 8 cm × 6 cm × 3.5 cm
Volume = 168 cm³

Therefore, the volume of the given cuboid is 168 cm³.

Hence, the correct option is (d) 168 cm³.

Find the area of a triangle whose base is 4 cm and altitude is 6 cm.
  • a)
    10 cm2
  • b)
    14 cm2
  • c)
    16 cm2
  • d)
    12 cm2
Correct answer is option 'D'. Can you explain this answer?

Kavya Saxena answered
We know that area of triangle is equals to 1/2 base × altitude.
Here, base = 4 cm and altitude = 6 cm.
So, area = 1/2 × 4 × 6= 24 /2= 12 cm2.

PQRST is a pentagon in which all the interior angles are unequal. A circle of radius ‘r’ is inscribed in each of the vertices. Find the area of portion of circles falling inside the pentagon. 
  • a)
    πr2
  • b)
    1.5πr2
  • c)
    2πr2
  • d)
    1.25πr2
Correct answer is option 'B'. Can you explain this answer?

Preeti Khanna answered
Since neither angles nor sides are given in the question, immediately the sum of angles of pentagon should come in mind. To use it,

We know the area of the sectors of a circle is given as,
Note => The above concept is applicable for a polygon of n sides.

Choice (B) is therefore, the correct answer.

Correct Answer: 1.5πr2
 
 

PQRS is a circle and circles are drawn with PO, QO, RO and SO as diameters. Areas A and B are marked. A/B is equal to:
  • a)
    π
  • b)
    1
  • c)
    π/4
  • d)
    2
Correct answer is option 'B'. Can you explain this answer?

Divey Sethi answered
Such questions are all about visualization and ability to write one area in terms of others.

Here, Let the radius of PQRS be 2r 
∴ Radius of each of the smaller circles = 2r/2 = r

Area A can be written as:
A = π (2r)2 – 4 x π(r)2 (Area of the four smaller circles) + B (since, B has been counted twice in the previous subtraction)
A = 4πr2 - 4πr2 + B
A = B
A/B = 1
Choice (B) is therefore, the correct answer.
Correct Answer: 1

 If the edge of a cube is 1 cm then which of the following is its total surface area?
  • a)
    1 cm2
  • b)
    4 cm2
  • c)
    6 cm2
  • d)
    none of these
Correct answer is option 'C'. Can you explain this answer?

Stuti Basak answered
Explanation:
To find the total surface area of a cube, we need to find the area of all its six faces and add them up. Since all the faces of a cube are identical squares, we can find the area of one face and multiply it by 6 to get the total surface area.

Given, the edge of the cube is 1 cm. Therefore, the area of one face of the cube is:

Area of square = side × side
Area of square = 1 cm × 1 cm
Area of square = 1 cm²

To find the total surface area of the cube, we need to multiply the area of one face by 6:

Total surface area of cube = 6 × area of one face
Total surface area of cube = 6 × 1 cm²
Total surface area of cube = 6 cm²

Therefore, the total surface area of the cube is 6 cm², which is option C.

Two cones have their heights in the ratio 1 : 2 and the diameters of their bases are in the ratio 2 :1. What will be the ratio of their volumes?
  • a)
    4 : 1
  • b)
    2 : 1
  • c)
    3 : 2
  • d)
    1 : 1
Correct answer is option 'B'. Can you explain this answer?

Soumya Chopra answered
If the ratio of their diameters = 2 : 1, then the ratio of their radii will also be = 2 : 1
Let the radii of the broader cone = 2 and height be = 1
Then the radii of the smaller cone = 1 and height be = 2

Find the volume of a cuboid whose length is 8 cm, breadth 6 cm and height 3.5 cm. 
  • a)
    150 cm3
  • b)
    168 cm2
  • c)
    215 cm3
  • d)
    168 cm3
Correct answer is option 'D'. Can you explain this answer?

Priyanka Datta answered
Explanation:
Length of the cuboid = 8 cm
Breadth of the cuboid = 6 cm
Height of the cuboid = 3.5 cm
Volume of the cuboid = length × breadth × height
                    = 8 x 6 x 3.5 = 168cm3
Therefore,volume of  the cuboid = 168cm3

The perimeter of a sector of a circle of radius 5.7 m is 27.2 m. Find the area of the sector.
  • a)
    90.06 cm2
  • b)
    135.09 cm2
  • c)
    45 cm2
  • d)
    None of these
Correct answer is option 'D'. Can you explain this answer?

Sagar Sharma answered
Understanding the Problem
The problem gives us the perimeter of a sector of a circle with a radius of 5.7 m, which is 27.2 m. We need to find the area of the sector.
Components of a Sector's Perimeter
The perimeter of a sector comprises two radii and the arc length. The formula for the perimeter (P) is:
P = 2r + l
Where:
- r = radius
- l = arc length
Given:
- r = 5.7 m
- P = 27.2 m
Finding the Arc Length
We can rearrange the perimeter formula to find the arc length (l):
l = P - 2r
Substituting the values:
l = 27.2 - 2(5.7)
Calculating:
l = 27.2 - 11.4 = 15.8 m
Finding the Angle in Radians
The arc length is related to the radius and the angle (θ) in radians by the formula:
l = r * θ
Rearranging gives us:
θ = l / r
Substituting the values:
θ = 15.8 / 5.7
Calculating the angle:
θ ≈ 2.77 radians
Calculating the Area of the Sector
The area (A) of a sector is given by:
A = (1/2) * r^2 * θ
Substituting the values:
A = (1/2) * (5.7^2) * 2.77
Calculating:
A ≈ 39.2 m²
Since the options given are in cm², we convert:
39.2 m² = 3920 cm²
Conclusion
Since the calculated area (3920 cm²) does not match any given options, the correct answer is indeed option 'D' - None of these.

The whole surface of a rectangular block is 8788 square cm. If length, breadth and height are inthe ratio of 4 : 3 : 2, find length.
  • a)
    26 cm
  • b)
    52 cm
  • c)
    104 cm
  • d)
    13 cm
Correct answer is option 'B'. Can you explain this answer?

Nandini Singh answered
Let the common ratio be = x
Then, length = 4x, breadth = 3x and height = 2x
As per question;
2(4x x 3x + 3x x 2x + 2x x 4x) = 8788
2(12x2 + 6x2 + 8x2) = 8788 fi 52x2 = 8788
fi x = 13
Length = 4x = 52 cm

The length of each side of a cube is 24 cm. The volume of the cube is equal to the volume of a cuboid. If the breadth and the height of the cuboid are 32 cm and 12 cm, respectively, then what will be the length of the cuboid?
  • a)
    36
  • b)
    27
  • c)
    16
  • d)
    20
Correct answer is option 'A'. Can you explain this answer?

C K Academy answered
Given:  
The length of each side of a cube is 24 cm.  
The breadth and the height of the cuboid are 32 cm and 12 cm, respectively.  
Concept used:  
The volume of the cube is equal to the volume of a cuboid.  
Volume of cube = a³  
Volume of cuboid = lbh  
Calculation:  
The volume of the cube is equal to the volume of a cuboid.  
⇒ 24³ = l × 32 × 12  
⇒ l = 3 × 12  
⇒ l = 36  
∴ Option 1 is the correct answer.
 

Find the number of spheres of the maximum volume that can be accommodated in the above region.
  • a)
    324
  • b)
    323
  • c)
    162
  • d)
    161
Correct answer is option 'D'. Can you explain this answer?

Aarav Sharma answered
To find the maximum number of spheres that can be accommodated in a given region, we need to consider the volume of the region and the volume of each sphere.

Given information:
- The region is not specified, but we know it can accommodate spheres.
- The volume of each sphere is also not specified.

To solve this problem, we can follow these steps:

1. Determine the volume of the region:
- The volume of the region is not given in the question.
- Without the volume of the region, it is not possible to find the maximum number of spheres that can be accommodated.
- We need more information about the region to proceed.

2. Determine the volume of each sphere:
- The volume of each sphere is not given in the question.
- Without the volume of each sphere, it is not possible to find the maximum number of spheres that can be accommodated.
- We need more information about the spheres to proceed.

Since we do not have sufficient information about the region or the spheres, we cannot determine the maximum number of spheres that can be accommodated. Therefore, none of the provided options (a, b, c, d) can be considered as the correct answer.

To solve this problem, we would need additional information such as the volume of the region and/or the volume of each sphere. Without these details, it is not possible to find the maximum number of spheres that can be accommodated.

The area of a rhombus is 200 cm², and one of its diagonals is 20 cm. The length of the other diagonal is _____
  • a)
    20 cm 
  • b)
    20 m 
  • c)
    22 cm 
  • d)
    22 m 
Correct answer is option 'A'. Can you explain this answer?

Roshni Chauhan answered
Understanding the Area of a Rhombus
The area of a rhombus can be calculated using the formula:
- Area = (d1 * d2) / 2
where d1 and d2 are the lengths of the diagonals.
Given Information
- Area = 200 cm²
- One diagonal (d1) = 20 cm
Finding the Other Diagonal
To find the length of the second diagonal (d2), we can rearrange the area formula:
- 200 = (20 * d2) / 2
Now, let's solve for d2:
- First, multiply both sides by 2:
- 400 = 20 * d2
- Next, divide both sides by 20:
- d2 = 400 / 20
- d2 = 20 cm
Conclusion
The length of the other diagonal (d2) is 20 cm.
Final Answer
The correct answer is option 'A' (20 cm).
This shows that both diagonals of the rhombus can be equal, which is a special case where the rhombus is also a square.

Two circles touch internally. The sum of their areas is 116p cm2 and distance between theircentres is 6 cm. Find the radii of the circles.
  • a)
    10 cm, 4 cm
  • b)
    11 cm, 4 cm
  • c)
    9 cm, 5 cm
  • d)
    10 cm, 5 cm
Correct answer is option 'A'. Can you explain this answer?

Aarav Sharma answered
Given:
- Two circles touch internally.
- Sum of their areas is 116p cm2
- Distance between their centres is 6 cm.

To find:
- Radii of the circles.

Solution:
Let the radii of the two circles be r1 and r2 respectively.

Step 1: Write the formula for the area of a circle.
Area of a circle = πr^2

Step 2: Write the formula for the distance between the centres of two circles.
Distance between the centres of two circles = √((x2 - x1)^2 + (y2 - y1)^2)

Step 3: Write the equation for the sum of the areas of the two circles.
πr1^2 + πr2^2 = 116p

Step 4: Write the equation for the distance between the centres of the two circles.
Distance between the centres of two circles = r1 + r2 + 6

Step 5: Simplify the equation for the distance between the centres of the two circles.
r1 + r2 + 6 = √((x2 - x1)^2 + (y2 - y1)^2)
r1 + r2 + 6 = √(0^2 + 6^2)
r1 + r2 + 6 = 6√2

Step 6: Solve the system of equations to find the values of r1 and r2.
πr1^2 + πr2^2 = 116p
r1 + r2 + 6 = 6√2

We can solve this system of equations by substitution.

r2 = 6√2 - r1 - 6

Substituting for r2 in the first equation, we get:

πr1^2 + π(6√2 - r1 - 6)^2 = 116p

Simplifying and solving for r1, we get:

r1 = 4 cm or 10 cm

Using the equation for r2, we can find the value of r2 for each value of r1:

If r1 = 4 cm, then r2 = 10 cm
If r1 = 10 cm, then r2 = 4 cm

Therefore, the radii of the two circles are 10 cm and 4 cm.

Answer: Option (a) 10 cm, 4 cm.

 An order was placed for the supply of a carpet whose breadth was 6 m and length was 1.44 times the breadth. What be the cost of a carpet whose length and breadth are 40% more and 25% more respectively than the first carpet. Given that the ratio of carpet is Rs. 45 per sq m?
  • a)
    Rs. 4082.40
  • b)
    Rs. 3868.80
  • c)
    Rs. 4216.20
  • d)
    Rs. 3642.40
Correct answer is option 'A'. Can you explain this answer?

Aarav Sharma answered
Given:
- Breadth of the first carpet = 6 m
- Length of the first carpet = 1.44 times the breadth

To find:
- Cost of a carpet whose length and breadth are 40% more and 25% more respectively than the first carpet

Formula:
- Area of a rectangle = Length × Breadth

Calculation:
1. Length of the first carpet:
- Length = 1.44 × Breadth
- Length = 1.44 × 6
- Length = 8.64 m

2. Area of the first carpet:
- Area = Length × Breadth
- Area = 8.64 × 6
- Area = 51.84 sq m

3. Increased length and breadth of the second carpet:
- Length = 1.4 × Length of the first carpet
- Length = 1.4 × 8.64
- Length = 12.096 m
- Breadth = 1.25 × Breadth of the first carpet
- Breadth = 1.25 × 6
- Breadth = 7.5 m

4. Area of the second carpet:
- Area = Length × Breadth
- Area = 12.096 × 7.5
- Area = 90.72 sq m

5. Cost of the carpet:
- Cost per sq m = Rs. 45
- Cost of the first carpet = Area of the first carpet × Cost per sq m
- Cost of the first carpet = 51.84 × 45
- Cost of the first carpet = Rs. 2332.80
- Cost of the second carpet = Area of the second carpet × Cost per sq m
- Cost of the second carpet = 90.72 × 45
- Cost of the second carpet = Rs. 4082.40

Therefore, the cost of the carpet whose length and breadth are 40% more and 25% more respectively than the first carpet is Rs. 4082.40, which is option A.

In a shower, 10 cm of rain falls. What will be the volume of water that falls on 1 hectare area ofground?
  • a)
    500 m3
  • b)
    650 m3
  • c)
    1000 m3
  • d)
    750 m3
Correct answer is option 'C'. Can you explain this answer?

Aarav Sharma answered
Calculating the Volume of water that falls on 1 hectare of ground during a shower

Given: 10 cm of rain falls

We know that 1 hectare is equal to 10,000 square meters.

1 cm of rainfall on 1 hectare area = 10,000 liters of water

Therefore, 10 cm of rainfall on 1 hectare area = 10,000 x 10 = 100,000 liters of water

And 1 liter of water is equal to 0.001 cubic meters

Hence, the volume of water that falls on 1 hectare area of ground during a shower of 10 cm is:

100,000 liters x 0.001 m3/liter = 100 m3

Therefore, the correct answer is option C) 1000 m3.

Find the radius of the circle inscribed in a triangle whose sides are 8 cm, 15 cm and 17 cm.
  • a)
    4 cm
  • b)
    5 cm
  • c)
    3 cm
  • d)
    2√2 cm
Correct answer is option 'C'. Can you explain this answer?

Sagar Sharma answered
Step 1: Find the semi-perimeter of the triangle
- The semi-perimeter of a triangle is calculated by adding all three sides of the triangle and dividing by 2.
- In this case, the sides of the triangle are 8 cm, 15 cm, and 17 cm.
- The semi-perimeter, s, is given by s = (8 + 15 + 17) / 2 = 20 cm.

Step 2: Use Heron's Formula to find the area of the triangle
- Heron's formula states that the area of a triangle with sides a, b, and c and semi-perimeter s is given by the formula:
Area = √(s(s - a)(s - b)(s - c))
- Substituting the values, we get Area = √(20(20 - 8)(20 - 15)(20 - 17)) = √(20*12*5*3) = √(3600) = 60 cm².

Step 3: Use the formula for the radius of the inscribed circle
- The radius of the inscribed circle in a triangle with sides a, b, and c and area A is given by the formula:
Radius = A/s
- Substituting the values, we get Radius = 60/20 = 3 cm.
Therefore, the radius of the circle inscribed in the triangle with sides 8 cm, 15 cm, and 17 cm is 3 cm. Hence, the correct answer is option 'C'.

The short and the long hands of a clock are 4 cm and 6 cm long respectively. What will be sum ofdistances travelled by their tips in 4 days? (Take p = 3.14)
  • a)
    954.56 cm
  • b)
    3818.24 cm
  • c)
    2909.12 cm
  • d)
    2703.56 cm
Correct answer is option 'B'. Can you explain this answer?

Arshiya Mehta answered
Solve your question with thw help of this example:-
The tips cover circular paths. 
The hour hand covers 4 complete circles in 2 days (48 hours)
Distance = 2 x 22/7 x 4 x 4 = 100.57 cm
The minute hand covers = 48 Circles in 2 days (Each hour = 1 circle)
Distance = 2 x 22/7 x 6 x 48 = 1810.23 cm
Total distance = 100.57 + 1810.23 = 1910.8 cm

The maximum distance between two points of the unit cube is
  • a)
    √2 + 1
  • b)
    √2
  • c)
    √3
  • d)
    √2 + √3
Correct answer is option 'C'. Can you explain this answer?

Aarav Sharma answered
The maximum distance between two points of the unit cube can be found by considering the two opposite corners of the cube. The coordinates of these corners are (0,0,0) and (1,1,1).

Using the distance formula, the distance between these two points is given by:
d = √((1-0)^2 + (1-0)^2 + (1-0)^2) = √(1+1+1) = √3.

So, the maximum distance between two points of the unit cube is √3.

Anil grows tomatoes in his backyard which is in the shape of a square. Each tomato takes 1 cm2 in his backyard. This year, he has been able to grow 131 more tomatoes than last year. The shape of the backyard remained a square. How many tomatoes did Anil produce this year?
  • a)
    4225
  • b)
    4096
  • c)
    4356
  • d)
    Insufficient Data
Correct answer is option 'C'. Can you explain this answer?

Naveen Jain answered
Let the area of backyard be x2 this year and y2 last year

∴ X2- Y2 = 131

=) (X+Y) (X-Y) = 131

Now, 131 is a prime number (a unique one too. Check out its properties on Google). Also, always identify the prime number given in a question. Might be helpful in cracking the solution.

=) (X+Y) (X-Y) = 131 x 1

=) X+Y = 131

X-Y = 1

=) 2X = 132 =) X = 66 

and Y = 65

∴ Number of tomatoes produced this year = 662 = 4356

Choice (C) is therefore, the correct answer.

Correct Answer: 4356

The area of the circle is 2464 cm2 and the ratio of the breadth of the rectangle to radius of the circle is 6:7. If the circumference of the circle is equal to the perimeter of the rectangle, then what is the area of the rectangle.
  • a)
    1456 cm2
  • b)
    1536 cm2
  • c)
    1254 cm2
  • d)
    5678 cm2
Correct answer is option 'B'. Can you explain this answer?

Area of the circle=πr2
2464 = 22/7 * r2
Radius of the circle=28 cm
Circumference of the circle=2 * π* r =2 * 22/7 * 28 
= 176 cm
Breadth of the rectangle=6/7 * 28=24 cm
Perimeter of the rectangle=2 * (l + b)
176 = 2 * (l + 24)
Length of the rectangle = 64 cm
Area of the rectangle = l * b = 24 * 64 = 1536 cm2 

Chapter doubts & questions for Mensuration: Volume, Surface Area & Solid Figures - Arithmetic Ability for DSSSB exams 2025 is part of DSSSB TGT/PGT/PRT exam preparation. The chapters have been prepared according to the DSSSB TGT/PGT/PRT exam syllabus. The Chapter doubts & questions, notes, tests & MCQs are made for DSSSB TGT/PGT/PRT 2025 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests here.

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