Question

The formula for the surface area, S, of a cone is shown below. solve the formula for the length l.

Answer 1

l =
`(S-\pi r^2)/(\pi r)`

Explanation:

S = πr² + πrl ( subtract πr² from both sides )

S - πr² = πrl ( isolate l by dividing both sides by πr )

`(S-\pi r^2)/(\pi r)` = l

Answer 2

`l = (S - \pi r^2)/(\pi r)`

Explanation:

`S = \pi r^2+\pi rl`

`\pi r^2+\pi rl = S`

`\pi rl = S - \pi r^2`

`l = (S - \pi r^2)/(\pi r)`