Mathematics for IGCSE & O level - Mensuration (Section 3 - No. 40)
If the radius of a sphere is halved, how does its surface area change?
It is halved.
It is quartered.
It is doubled.
It is multiplied by 8.
คำอธิบาย
The surface area of the sphere = 4πr². When the radius is halved, the surface area becomes 4π(r/2)² = πr²