A rectangular pool is 12 ft wide, 20 ft long and 5 ft deep. If it is 4/5 full, how much water does it contain?

Can someone me with my math problem pls my teacher is on my back about this

Grace is standing 18 feet from a lighthouse and kelly is standing 10 feet from grace. the angle that grace looks up to see the top of the lighthouse is 45°. the angle that kelly looks up to see the top of the lighthouse is y°. find the height, h, of the lighthouse. find the angle, rounded to the nearest tenth of a degree, in which kelly looks up to the top of the lighthouse. to the nearest tenth of a degree, find the value of x° . in two or more sentences, explain your calculations

What is the output, or dependent variable of quantity? 1: x 2: f(x) 3: y