Question

The radius of sphere A is twice that of a sphere B. Find the ratio among their surface areas and the ratio among their volumes.

Answer 1

radius of sphere A= 2r

radius of sphere B= r

now ratio of volume of spheres= 4/3πr3=4/3πr3
=r3=r3
=8r3=r3
=8:1

now,
ratio of area of spheres=4πr2=4πr2
=4r2=r2
=4:1

I hope u understand

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Answer 2

hey,let radius of sphere A be=r
radius of sphere be=2r

volume=4/3πr³

then,

4/3*πr³=4/3*π*(2r) ³

r³=8r³

hence there volume ratio is 1: 8

T. S. A of sphere=4πr²

4πr²=4π(2r) ²

r²=4r²


then ratio of their surfaces=1: 4


hope bit helps you