Question

Solve s=πr^2+πrl for l

Answer 1

Start with

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

Subtract
`\pi r^2` from both sides:

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

Divide both sides by
`\pi r`

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

And thus we solved the expression for l:

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