Question

if the radius of a sphere is increased by 5 cm its surface area increases by 704 cm^2 find its radius before this increase

Answer 1

Hola Friend ✋✋✋

♦ Let the original radius be 'r'

And orginal area is 4πr²

♠ When radius is increased by 5cm

then radius is ' r + 5 '

And area will be 4π × ( r + 5 )² = 704cm²


4 × π × ( r + 5 )² = 704

( r + 5 ) ² = 704/4 × 7 /22

( r + 5 ) ² = 56

r + 5 = √56

r = 2√14 - 5

Hope it helps