If i want to build a fence around my rectangular yard, what is the area in fencing if one side is 50 feet long and the other is 80 feet wide?

Caleb and emily are standing 100 yards from each other. caleb looks up at a 45° angle to see a hot air balloon. emily looks up at a 60° angle to see the same hot air balloon. approximately how far is the hot air balloon off the ground? a)44.2 yd. b)63.4 yd. c)73.2 yd. d)89.7 yd.