I need help with the following problem:

You're in a hot air balloon with your support crew on the ground. Attached to the balloon are two tether cords of length 350 feet and 400 feet that your crew attached to the ground. These cords form an angle of 50 degrees where they meet the balloon. Assuming the lines are taut and the ground is level, what is the distance between the points on the ground where the two tether cords are attached?

think back, back, back to your days in trig.

d^2 = 350^2 + 400^2 - 2*350*400*cos 50
d = 320.19