Please help im super behind :((

What is the length of the unknown leg in the right triangle ?

Identify a1 and r for the geometric sequence an= -256(-1/4) n-1

10 ! a train starts from grand city and travels toward belleville 388 miles away. at the same time, a train starts from belleville and runs at the rate of 47 miles per hour toward grand city. they pass each other 4 hours later. find the rate of the train from grand city.