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 8 inches deep?
when h=2/3 ft
The Attempt at a Solution
I tried doing it the straightforward way:
This is wrong. Then I tried using similar triangles to get the new base to go along with the height of 8 in. For that I got 10/3 ft. So,
This is also incorrect. I really don't know why. Any help would be greatly appreciated!