A bird-(B) is spotted flying 5,000 feet from a tree (T). An observer (O) spots the bird (B) at a distance of 13,000 feet. What is the angle of depression from the bird to
the observer (O)?

This size running track is usually called a 400 meter track. however if a person ran as close to the inside as possible on the track they would run less than 400 meters in one lap. how far away from the inside border would someone have to run to make one lap equal exactly 400 meters