I don’t remember how to do this! please help

Aplane flies around trip to philadelphia it flies to philadelphia at 220 miles per hour and back home with a tailwind at 280 miles per hour if the total trip takes 6.5 hours how many miles does the plane fly round trip

Ten times the square of a non-zero number is eqaul to ninety times the number

In the diagram, ab is tangent to c, ab = 4 inches, and ad = 2 inches. find the radius of the circle.