1.
The radius of a cylinder is 12 m, height 21 m. the lateral surface area of the cylinder is:
Answer: Option 'C'
Lateral surface area = 2πrh
= 2 × 22/7 × 12 × 21
= 44 × 36
= 1584 m2
2.
The radius of a cone is 4 m, height 5 m. Find the curved surface area?
Answer: Option 'B'
Cone curved surface area = πrl = 22/7 × 4 × 5 = 440/7 = 62 6/7
Slant height (l) = √r2+h2 = √16+9 = √25 = 5
3.
The radius of hemi-sphere is 14 m. find its cutved surface area?
Answer: Option 'D'
Curved surface area = 2πr2
2 (22/7) × 14 × 14
44 × 28
1238 sq.units
4.
A cylinder and a cone have the same height and same radius of base. The ratio between the volumes of the cylinder and the cone is:
Answer: Option 'A'
Volume of the cylinder = πr2h
Volume of the cone = 1/3 πr2h
(πr2h)/(1/3 πr2h) = 3/1 = 3 : 1
5.
Two cubes of thire sides ratio 2 : 3. Find its cube volumes ratio?
Answer: Option 'C'
a3 : b3 = 23 : 33
= 8 : 27