Question

The radius of sphere is r cm it is divided into two equal parts find the whole surface of two parts.

Answer 1

Whole Surface area of a part=3πr^2
Therefore,Whole surface area if 2 parts=2×3πr^2=6πr^2

Answer 2

Whole surface area of each part :-

$\bf\huge 2\pi r^2 + \pi r^2$

= $\bf\huge 3\pi r^2$

Total surface area of two parts :-

$\bf\huge 3\pi r^2$ +  $3\pi r^2$

= $\bf\huge 6\pi r^2$