Question

if the radius of a sphere is halved then the decrease in its surface area is​

Answer 1

Answer:

(i)  decrease in surface area is 4πr² - 1πr² = 3πr²

(ii) decrease in surface area is 75%

Step-by-step explanation:

let the radius of the sphere be = r

then surface area will be 4πr² ............. (i)

now if the radius is halved then let the radius be = r/2

then the surface area will be 4π(r/2)² = 4πr²/4 = 1πr².........(ii)

decrease in surface area is 4πr² - 1πr² = 3πr²

percentage of decrease in area in area will be 3πr²/4πr² × 100

=> 3 / 4 × 100

=> 3 × 25 = 75%

decrease in surface area is 75%

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