WAEC - Mathematics (2024 - No. 15)

Make R the subject of the relation V = πl(R\(^2\) - r\(^2\))

R = \(\sqrt{\frac{V}{πl} + r^2}\)

R = \(\sqrt{\frac{V}{πl} - r^2}\)

R = \(\sqrt{V - πlr^2}\)

R = \(\sqrt{V + πlr^2}\)

V = πl(R\(^2\) - r\(^2\))

Divide both sides by πl

\(\frac{V}{πl}\) = (R\(^2\) - r\(^2\))

R\(^2\) = \(\frac{V}{πl}\) + r\(^2\)

Take the square root of both sides

R = \(\sqrt{\frac{V}{πl} + r^2}\)