Where does the pythagorean identity sin^2 θ + cos^2 θ = 1 come from? how does it relate to right triangles?

Aswimming pool has an input pump for filling the pool and an output pump for emptying the pool. the input pump can fill the pool in 3 hours, and the output pump can drain the pool in 5 hours. as you go to bed, the pool is full, but a neighbor’s kid turns on the output pump. at midnight, you awake to find the pool half empty. immediately, you turn on the input pump, but you are sleepy and forget to turn off the output pump. at what time will the pool become full?

Manny bought 12 pounds of vegetables at the supermarket. 75% of the vegetables were on sale. how many pounds of vegetables were not on sale? 98 points : )

You receive 15% of the profit from a car wash how much money do you receive from a profit of 300