Given the right triangle pictured to the right. Suppose that a=5 feet and c=13 feet. Suppose side ‘a’ begins stretching to the right at a rate of 3 ft/min. As this happens, side ‘b’ remains constant and side ‘c’ stretches with it. Find the rate at which the measure of angle θ is changing at the moment when side ‘a’ has stretched to 12 feet in length. (10 points)