Question

The radius of the base of a solid cone is r cm and its height is h cm; its curved surface area is ______.

Options

• \[\pi \times r \times \sqrt{h^{2}-r^{2}}\]

• \[\pi \times r \times \sqrt{h^{2}+r^{2}}\]

• \[\pi \times r \times(h+r)\]

• \[\pi r^{2}(h+r)\]

Answer 1

The radius of the base of a solid cone is r cm and its height is h cm; its curved surface area is \[\underline{\boldsymbol{\pi \times r \times \sqrt{h^2 + r^2}}}\].

Explanation:

By formula,

Curved surface area = πrl

= \[\pi \times r \times \sqrt{h^{2}+r^{2}}\]