Question

A cosmetics company that makes small cylindrical bars of soap wraps the bars in plastic prior to shipping. Find the surface area of a bar of soap if the diameter is 5cm and the height is 2cm.

Answer 1

The formula you use is pi x radius ^ 2 + pi x radius x l ( l stands for lateral height)
pi x 2.5^2 + pi x 2.5(2)
3.14 x 6.25 + 3.14 x 5
19.6 + 15.7
= 35.3 cm^2

Answer 2

we would have two circles of 5cm diameter each, and a rectangle of the length pi*diameter and 2cm, so lets add them:
total = 2circles + rectangle
total = 2(2*pi*(5/2)^2) + pi*diameter*heigth
= 4*pi*(2.5)^2 + pi*5*2
= 109.9
that is the surface area of a bar soap 109.9 cm^2