Question

area of the bowl.
9: The radius of a sphere is decreased by 20 %. DJ
what per cent its curved surface area decreases ?
four spheres​

Answer 1

Let the diameter of sphere be "d"

surface area of sphere , S = 4πr²

= π (2r)²

= π(d)²

Diameter of sphere decreases by 20%

New diameter = d - (d/5) = [5d- d] / 5 = 4d/5

New surface area , S' = π(4d/5)²

= (16/25) πd²

Change in surface area of sphere = S - S'

= πd² – (16/25) πd²

= (9/25) πd²

Decrease in surface area = [(9/25πd²) / πd²] x 100 = 9 / 25 × 100 = 36 %

Therefore the decrease in S.A of sphere is 36%

pls mark it as brainliest

Answer 2

Step-by-step explanation:

This is the answer hope this helps you