Question

Some identical cylinders each have a radius of

5 cm and a length of 4 cm.
Rufus has enough paint to cover 2500 cm².
How many of these cylinders can Rufus paint
completely?

Answer 1

8 cylinders

Explanation:

The surface area of a cylinder is given by the formula ...

A = 2πr(r +l) . . . . . for radius r and length l

__

The cylinders Rufus has each have an area of ...

A = 2π(5 cm)(5 cm +4 cm) = 90π cm² ≈ 282.74 cm²

That means 2500 cm² of paint will cover ...

2500 cm²/(282.74 cm²/cylinder) ≈ 8.84 cylinders

Rufus has enough paint to cover 8 cylinders completely.