Question

The paper cup is 9 cm tall and the circular opening has a radius of 2.5 cm.

What is the minimum amount of paper needed to make the paper cup to the nearest whole cm² assuming no overlap in the paper?

Answer 1

Explanation:

Assume that the cup is a cylinder of height 9 cm and radius 2.5 cm.

The side area is A = (circumference)(height), or A = 2πrh, which here is:

A = (3.14)(2)(2.5 cm)(9 cm) = 141.37 cm²

and

The area of the bottom is A = πr², or (here) A = (3.14)(2.5 cm)² = 19.63 cm²

Adding together the area of the sides and the area of the bottom, we get

Total area of cup = 141.37 cm² + 19.63 cm² = 161 cm²