Solve to get the value of h

Charles is on a 8 1/2 mile bike ride. he stops for a rest after he’s gone 5 2/5 miles. how much farther does he still have to go?

Can someone me with these two circle theorem questions asap?

Which is the correct first step in finding the area of the base of a cylinder with a volume of 26x cubic meters and a height of 6.5 meters? v=bh 6.5=b(26x) v=bh v=26pi+(6.5) v=bh v=26pi(6.5) v=bh 26pi=b(6.5)