Determine the volume of the triangular prism in cubic feet

Planning for the possibility that your home might get struck by lighting and catch on fire is part of a plan

An architect is designing a water fountain for a park she uses the given function to model the water jet flowing from the fountain nozzles where h(x) gives the height of the water jugs in feet x feet from the starting point h(x)=-1/20x+x+15

Find the equation using the point (4,8)