Question

W=2PR/R-r; solve for P

Answer 1

`\boxed{ \sf\:P=(W\left(R-r\right))/(2R)}`

Explanation:

`\sf\:W = \frac { 2 P R } { R - r }`

`\sf\:W\left(-r+R\right)=2PR`

`\sf\:-Wr+WR=2PR`

`\sf\:2PR=-Wr+WR`

`\sf\:2RP=RW-rW`

`\sf(2RP)/(2R)=(W\left(R-r\right))/(2R)`

`\boxed{ \sf\:P=(W\left(R-r\right))/(2R)}`

Hope it helps ⚜