Question

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

Options

• 4πr² sq.units

• 6πr² sq.units

• 3πr² sq.units

• 8πr² sq.units

Answer 1

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

Explanation:

Because a hemisphere's curved surface area is, we unite two solid hemispheres along their bottoms of radii r to form a solid sphere.

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