Question

A cone has a circular base with a diameter of 18 inches the height of the cone is 40inches what is the approximate lateral area of the cone

Answer 1

Answer:

$A=1158.66\ \text{inches}^2$

Step-by-step explanation:

Given that,

The diameter of the base of a circular cone, d = 18 inches

Height of the cone, h = 40 inches

We need to find the lateral surface area of the cone. The formula of the lateral surface of the cone is given by :

$A=\pi rl$

l is the slant height of the cone,

$l=\sqrt{r^2+h^2} \\\\l=\sqrt{(9)^2+(40)^2} \\\\l=41\ \text{inches}$, d = 18 inches, r = 9 inches

So,

$A=3.14\times 9\times 41\\\\A=1158.66\ \text{inches}^2$

So, the lateral surface area of the cone is $1158.66\ \text{inches}^2$.