D and E are midpoints of AB and BC, respectively. Is DC parallel to AC?

I’m still confused on how to work the percentages

Marion has a bicycle that she is planning to take for a ride. the rim of the rear wheel lies 41 cm from the center of the wheel. the tire itself has a thickness of 3 cm. in order for marion to ride her bicycle 96,712 cm approximately how many rotations will the rear wheel make?

Asail is in the form of a right triangle that is 3 times as high as it is wide. the sail is made from 6 square meters of material. what is the height?