Question

Find the slant height of a frustum cone whose top radius is 12 cm and bottom radius is 7 cm. The height of the cone is 12 cm.

• A. 15 cm
• B. 13 cm
• C. 10 cm
• D. 14 cm

Answer 1

The correct option is B 13 cm

Formula of slant height is given by $L^2=h^2+(R-r{)}^2$

Given $h=12cm,R=12cm,r=7cm$

by substituting the values we get:

$L^2={12}^2+(12-7{)}^2$

$L^2=144+25$

$L^2=169$

$L=13cm$