Page 83 - Mathematics Class - IX

MCQs

1. In a cylinder, if radius is halved and height is doubled, the volume will be
a) same b) doubled c) halved d) four times

2. The radius of a sphere is 2r, then its volume will be
4 8pr 3 32
a) pr 3 b) 4 pr 3 c) d) pr 3
3 3 3
3. The total surface area of a cone with radius r/2 and slant height 2l is
r
a) 2pr (l + r) b) pr (l + ) c) pr (l + r) d) 2prl
4
4. The radii of two cylinders are in the ratio of 2:3 and their heights are in the ratio of 5:3. The ratio of
their volumes is

a) 10 : 17 b) 20 : 27 c) 17 : 27 d) 20 : 37

32 r
Answers: 1. c) halved 2. d) pr 3 3. b) pr (l + ) 4. b) 20 : 27
3 4

Case-Study Based Questions
Case-Study Based Questions

A building was constructed by Mohan. In this building, 15 cylindrical pillar were constructed. Now all these
pillars were to be painted. The diameter of each pillar was 48 cm and height was 7 cm.

Answer the following questions on the basis of the above data.
1. What is the radius of each pillar in m?
(i) 9.6 m (ii) 2.4 m (iii) 0.96 m (iv) 0.24 m
2. Which area should be calculated to know the requirement of paint?

(i) Total S.A. (ii) Curved S.A.
(iii) Area of top (iv) Curved S.A. + Area of top
3. What is the formula to find curved S.A. of cylinder?
(i) πrh (ii) 2πrh (iii) πr h (iv) 2πr h
2
2
4. Find the curved S.A. of one cylindrical pillar.
(i) 856 m (ii) 1056 m (iii) 1256 m (iv) 656 m 2
2
2
2

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