Question

if the radius of a sphere is doubled then how many items it's surface area increase​

Answer 1

because

we clearly know that surface area of sphere = 4πr²

and if the radius of a sphere is doubled then obviously the surface will alsoo increase !!!

Answer 2

SA₁ of sphere = 4πr²

Radius is doubled. Hence new radius becomes 2r.

SA₂ after increasing r = 4π (2r)²

= 4 (4πr²)

= 4 SA₁

Hence SA increases 4 times.