Find the surface area of a sphere of radius:
(i) 10.5 cm (ii) 5.6 cm (iii) 14 cm
(i) 1386 cm² (ii) 394.24 cm² (iii) 2464 cm²
Find the surface area of a sphere of diameter:
(i) 14 cm (ii) 21 cm (iii) 3.5 m
(i) 616 cm² (ii) 1386 cm² (iii) 38.5 m²
Find the total surface area of a hemisphere of radius 10 cm. (Use π = 3.14)
942 cm²
The radius of a spherical balloon increases from 7 cm to 14 cm as air is being pumped into it. Find the ratio of surface areas of the balloon in the two cases.
1 : 4
A hemispherical bowl made of brass has inner diameter 10.5 cm. Find the cost of tin-plating it on the inside at the rate of ₹16 per 100 cm².
₹27.72
Find the radius of a sphere whose surface area is 154 cm².
3.5 cm
The diameter of the moon is approximately one fourth of the diameter of the earth. Find the ratio of their surface areas.
1 : 16
A hemispherical bowl is made of steel, 0.25 cm thick. The inner radius of the bowl is 5 cm. Find the outer curved surface area of the bowl.
173.25 cm²
A right circular cylinder just encloses a sphere of radius r. Find:
(i) surface area of the sphere
(ii) curved surface area of the cylinder
(iii) ratio of the areas obtained in (i) and (ii)
(i) 4πr² (ii) 4πr² (iii) 1 : 1