Question

If two solid hemispheres of same base radius r are joined together along their bases, then curved surface area of this new solid is ______.

Options

• 4πr²

• 6πr²

• 3πr²

• 8πr²

Answer 1

If two solid hemispheres of same base radius r are joined together along their bases, then curved surface area of this new solid is 4πr².

Explanation:

Because curved surface area of a hemisphere is 2πr² and here, we join two solid hemispheres along their bases of radius r, from which we get a solid sphere.

Hence, the curved surface area of new solid = 2πr² + 2πr² = 4πr².