The lateral surface area of a cuboid, whose length, breadth and height are 12 cm, 8 cm, and 4.5 cm, respectively, is ____.

Correct! Wrong!

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Given, length, l=12 cm, Breadth, b = 8 cm, Height, h = 4.5 cm We know that, Lateral surface area of a cuboid =2h(l+b) =2×4.5(12+8) =9×20 =180 cm2 Hence, the lateral surface area of the cuboid is 180 cm2.

If the volume of a cube is 729 cm3, then its total surface area is ____.

Correct! Wrong!

Let the length of the edge of the cube be l cm. Given, the volume of cube = 729 cm3 ⇒ l3 = 729 ⇒ l = 9 We know that, Total surface area of the cube = 6 l2 = 6 × 81 = 486 cm2 Hence, the total surface area of cube is 486 cm2

If the difference between the total surface area and the lateral surface area of a cube is 50 m2, then the length of edge of the cube is ____.

Correct! Wrong!

Let a be the length of edge of the cube. Lateral surface area of a cube = 4 a2 Given, 6 a2 - 4 a2= 50 m2 ⇒ 2 a2 = 50 ⇒ a2 = 25 ⇒ a = 5 m Hence, the length of edge of the cube is 5 m.

If the radius and height of a cylinder are 10cm, 14cm respectively, then its lateral surface area is ____.

Correct! Wrong!

Given, height of the cylinder, h = 14 cm, Radius of the cylinder, r = 10 cm Lateral surface area of the cylinder = 2 πrh = 2 × 22 /7 × 10 × 14 = 880 cm2 Hence, the lateral surface area of the cylinder is 880 cm2

If the radius and height of a cylinder are r and h respectively, then its volume is ____.

Correct! Wrong!

If the radius and height of a cylinder are r and h respectively, then its volume is π r2h

If the length, breadth and height of a cuboid are 24 cm, 6 cm and 5 cm respectively, then its total surface area is ____.

Correct! Wrong!

Given, length, l = 24 cm, Breadth, b = 6cm, Height, h = 5cm We know that, Total surface area of a cuboid = 2(lb + bh +lh) = 2(24 × 6 + 6 × 5 + 5 × 24) = 2(144 + 30 + 120) = 2 × 294 = 588 cm2 Hence, the total surface area of the cuboid is 588 cm2

The number of cubes of edge 2 cm can fit in a box of volume 480 cm3 is ____.

Correct! Wrong!

Let the length of edge of the cube be a and the number of cubes be n. Given, a = 2 cm and volume of the box =480 cm3 ⇒n× a3=480 ⇒n×8=480 ⇒n=60 Hence, the required number of cubes is 60.

Curved surface area of a roller is 264 m2 If it takes the roller 10 revolutions to level a piece of ground, area of the ground is 2640 m2

Correct! Wrong!

Area of the ground = 10 × curved surface area of the roller = 10 × 264 =2640 m2 Hence, the area of the ground is 2640 m2

If the height and radius of a right circular cylinder are 35 cm and 5 cm respectively, then the volume of the cylinder is ____.

Correct! Wrong!

Given, height of the cylinder, h= 35cm Radius of the cylinder, r = 5cm Volume of the cylinder, V = π r2h = 22 /7 × 5 × 5 × 35 = 2750 cm3 ∴ The volume of the cylinder is 2750 cm3

The breadth and height of a cuboid are 5 cm and 2 cm respectively. If the volume of the cuboid is 50 cm3, then its length is ____.

Correct! Wrong!

Given, volume of cuboid (V) = 50 cm3 Height of cuboid (h) = 2 cm, Breadth of cuboid (b) = 5 cm We know that, V = lbh ⇒ 50 = l × 5 × 2 ⇒ l = 50 /10 ∴ Length of the cuboid = 5 cm

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CBSE Class 9th Math 13 - Surface Areas and Volumes MCQs
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