Question

you buy two rolls of wrapping paper. each roll has the same lateral surface area. what is the diameter of roll B?

Answer 1

The area of lateral surface is equal that the perimeter multiply by the length. So the lateral surface area of roll A is 3*π*30=90π. Roll B: d*π*24=24dπ. Put them together: 90π=24dπ. So d=3.75 in.