There is a ratio 1 : 4 between surface area of two spheres, find the ratio between their radius.
Let radius of spheres are r1 and r2
So, surface area of spheres is 4πr12 and 4πr22
Ratio of surface area = 4πr12/ 4πr22 = ¼
= r12/r22 = ¼
r1/r2 = 1/2
Hence, the ratio between their radius = 1 : 2.