Question

A cylindrical solid whose radius and height are equal has a surface area of 154cm2.Calculate its radius?

Answer 1

surface are = 2 end circles + "sleeve" of cylinder

2πr^2 + 2πrh = 154 , where r is the radius and h is the height
but h = r
2πr^2 + 2πr^2 = 154
r^2 = 77/π
r = √(77/π)
= .....