Q4 of 70 Page 23

The surface area of a sphere is 5544 cm2, find its diameter.

Let the radius of the sphere be r cm.


We know that, surface area of a sphere = 4πr2


Given, surface area of a sphere is 5544 cm2


⇒ 4πr2 = 5544


⇒ 4× × r 2 = 5544


⇒ r2 = 441


⇒ r = 21 cm


Thus diameter = 42 cm


More from this chapter

All 70 →
2

Find the surface area of a sphere of diameter :

(i) 14 cm


(ii) 21 cm


(iii) 3.5 cm

 3

Find the total surface area of a hemisphere and a solid hemisphere each of radius 10 cm. (Use π = 3.14)

 5

A hemispherical bowl made of brass has inner diameter 10.5 cm. Find the cost of the plating it on the inside at the rate of Rs. 4 per 100 cm2.

 6

The dome of a building is in the form of a hemisphere. Its radius is 63 dm. Find the cost of painting it at the rate of Rs. 2 per sq. m.