1. The problem statement, all variables and given/known data A trough is 9 ft long and its ends have the shape of isosceles triangles that are 5 ft across at the top and have a height of 1 ft. If the trough is being filled with water at a rate of 14 ft3/min, how fast is the water level rising when the water is 7 inches deep? I know b, h, l, dv/dt, dl/dt. I need to first find db/dt then solve for dh/dt 2. Relevant equations Volume of Iso. triangular prism= 1/2bh*l dv/dt=1/2bh(dl/dt)+l(1/2b(dh/dt)+1/2h(db/dt) I assume that dl/dt=0, so the new equation for the derivative is equal to.. dv/dt=l(1/2b(dh/dt)+1/2h(db/dt) 3. The attempt at a solution If anyone could just give me some direction where to start in solving for db/dt that would be great!