There is a ratio 1 : 4 between surface area of two spheres, find the ratio between their radius.
Let radius of spheres are r_{1} and r_{2}
So, surface area of spheres is 4πr_{1}^{2} and 4πr_{2}^{2}
Ratio of surface area = 4πr_{1}^{2}/ 4πr_{2}^{2} = ¼
= r_{1}^{2}/r_{2}^{2} = ¼
r_{1}/r_{2} = 1/2
Hence, the ratio between their radius = 1 : 2.