Wrapping the World A ribbon is tied tightly around the earth at the equator. How much more ribbon would you need if you raised the ribbon 1 ft above the equator everywhere? (You don’t know the radius of the earth to solve this problem.)

To estimate:

The additional length of the ribbon required

Given that, the ribbon is tied tightly round the equator.

Considering the earth as a perfect sphere of radius r, the circumference of the earth is given by 2πr.

Therefore, the length of the ribbon R1 is given by 2πrft.

(i.e.) R1=2πrft.

Also, given that the ribbon is raised 1ft above the equator everywhere.

Which implies that the new radius required for the earth to fit the ribbon is r+1.

Hence, the new circumference of the earth is given by 2π(r+1).

Therefore, the length of the ribbon R2 is given by 2π(r+1)ft.

(i.e.) R2=2π(r+1)ft