Question

Find the slant height of a frustum cone whose top radius is 5 m and bottom radius is 12 m. The height of the cone is 24 m.

• A. 25 m
• B. 23 m
• C. 20 m
• D. 24 m

Answer 1

The correct option is A 25 m

Slant height, $L^2=h^2+(R-r{)}^2$

$L^2={24}^2+(12-5{)}^2$

$L^2=576+49$

$L^2=625$

Squaring on both sides, we get

L = 25 m