A solid cylinder of radius 3cm has a total surface area of 36\(\pi\)cm2. Find its height
A
2cm
B
3cm
C
4cm
D
5cm
E
6cm
Verified Correct Answer: B.
Step-by-Step Mathematical Solution
Area 2\(\pi\)r2 + 2 \(\pi\)r(r + h)
= 2\(\pi\)r(r + h)
36\(\pi\) = 6\(\pi\)(r + h)
36\(\pi\) = 6\(\pi\)(3 + h)
36\(\pi\) = 18\(\pi\) + 6\(\pi\)h
36\(\pi\) - 18\(\pi\) = 6\(\pi\)h
Divide both side by 6\(\pi\)
h = 3cm
Source: Myschool Past Questions Archive (Record #32614)