What is the range of possible sizes for side X

Passengers usually start to board their flights 1 hour before the scheduled take off time. the gate will be closed 15 minutes before the takeoff time. jack’s plane is scheduled to take off at 12: 05 a.m. if he arrives at the gate at 11: 45 p.m., can he board the flight?

With #! i’ve tried to figure it out but i can’t.

A.s.a.! similarity in right triangles, refer to the figure to complete this proportionc/a = a/? a.) cb.) hc.) rd.) s