4. The height of a triangular fin emerging from the ocean increases at 5 in/s as the length of its base along the water surface increases at 2 in/s. (a) Draw and label a picture. Write an equation for the area of the fin above the water in terms of variables from this picture. (b) When the area of the fin above the water is 6 in² and its height is 3 in, how fast is its area above the water increasing? Include units.