Chapter 12.3, Problem 5ACYP

To determine

Find the surface area of the cone.

Answer to Problem 5ACYP

S = $7.5m{m}^2$

Explanation of Solution

Given:

  

Formula Used: The Lateral area L of cone is

  $L=\pi rl$ , where l is the slant height and r is the radius of the base.

The Surface area S of cone is

  $S=L+\pi r^2$ , where r is the radius of the base.

Calculation:

Radius of the cone is 0.8 mm and slant height is 2.2 mm.

Lateral area of the cone = $L=\pi rl=\pi (0.8)(2.2)\approx 5.5m{m}^2$

Surface area of the cone = $S=L+\pi r^2=5.5+\pi {(0.8)}^2=5.5+2.01\approx 7.5m{m}^2$

Hence,

S = $7.5m{m}^2$