a trough is 9 feet long, and its cross section is in the shape of an isosceles right triangle with hypotenuse 2 feet, as shown above. water begins flowing into the empty trough at the rate of 2 cubic feet per minute. at what rate is the height h feet of the water in the trough changing 2 minutes after the water begins to flow? responses decreasing at 23 foot per minute decreasing at two thirds foot per minute increasing at 23 foot per minute increasing at two thirds foot per minute decreasing at 16 foot per minute decreasing at one sixth foot per minute increasing at 16 foot per minute