Answer:
foot = 5 ft
luff = 20 ft
Step-by-step explanation:
In the picture attached, the diagram of the sail is shown. A right triangle is formed, where 50 ft² is its area, which can be computed as follows:
foot*luff*1/2 = 50
We also know that luff = 4*foot. Replacing into the previous equation:
foot*(foot*4)*1/2 = 50
foot²*2 = 50
foot² = 50/2
foot = √25
foot = 5 ft
luff = 4*5 = 20 ft