Question

Find the surface areas and volumes of spheres of the following radii 

i. 4 cm 

ii. 9 cm 

iii. 3.5 cm (π = 3.14)

Answer 1

i. Given: Radius (r) = 4 cm 

To find: Surface area and volume of sphere 

Surface area of sphere = 4πr² 

= 4 x 3.14 x 4² 

∴ Surface area of sphere = 200.96 sq.cm 

Volume of sphere = (4/3) πr³ 

= (4/3) x 3.14 x 4²

 ∴ Volume of sphere = 267.95 cubic cm

ii. Given: Radius (r) = 9 cm 

To find: Surface area and volume of sphere 

Surface area of sphere = 4πr² 

= 4 x 3.14 x 9² 

∴ Surface area of sphere = 1017.36 sq.cm

∴ Volume of sphere = 3052.08 cubic cm 

iii. Given: Radius (r) = 3.5 cm 

To find: Surface area and volume of sphere 

Surface area of sphere = 4πr²

= 4 x 3.14 x (3.5)² 

∴ Surface area of sphere = 153.86 sq.cm 

Volume of sphere = (4/3) πr³ 

= (4/3) x 3.14 x (3.5)³ 

∴ Volume of sphere = 179.50 cubic cm