Question

A roller coaster rises and falls on a semicircular portion of track that has a radius of curvature of 20 m.

Answer 1

the distance traveled by the roller coaster is equal to the circumference of the  semicircle

Since, the roller coaster travels only above the track the formula will be....

πr²

π x 20 x 20

400π

400 x 3.14

1256 m²