Make h the subject of the formula s= 2πr(r+h)
s = 2πr(r+h)
s/2πr = r+h
(s/2πr)-r = h
Be careful with brackets
s= 2πr(r+h)
s/(2πr) = r + h
h = s/(2πr) - r
X's solution would be dividing only by 2 not by 2πr
s/2πr = r+h
(s/2πr)-r = h
s= 2πr(r+h)
s/(2πr) = r + h
h = s/(2πr) - r
X's solution would be dividing only by 2 not by 2πr