Question

The lateral surface area S of a cone can be found by using the formula S= pi x R square root (R^2 + h^2), where r is the radius of the base and H is the height of the cone. Find the height of the cone. surface area is 121 and r is 3 (try finding h by rearranging the formula)

Answer 1

12.483

Explanation:

`S=\pi r\sqrt{r^(2) +h^(2) }`

`121=\pi 3\sqrt{3^(2) +h^(2) }`

`121 =9.425\sqrt{3^(2) +h^(2) }`

`12.838^(2) =\sqrt{3^(2) +h^(2) }^(2)`

`164.814=3^(2) +h^(2)`

`164.814=9 +h^(2)`

`155.814=h^(2)`

`√(155.814)=\sqrt{ h^(2)`

12.483=h