Question

The lateral area of a cone is 400 pi cm^2. The radius is 10 cm. Find the slant height to the nearest tenth.

Answer 1

ANSWER

The slant height is 40cm.

EXPLANATION

The lateral area of a cone is given by:

$Area= \pi \: r \: l$

where r=10cm is the radius of the circle and l is the slant height.

It was also given that, the lateral area is 400π cm²

We substitute the values to get,

$400\pi = \pi \times \: 10 \times \: l$

We now divide both sides by 10π.

This implies that,

$\frac{400 \pi}{10\pi} = l$

$40 = l$

Hence the slant height is 40cm.