Need ! a contractor is calculating how many shingles he must purchase to re-roof a building. one section of the roof has the shape of an isosceles triangle, with a base that is 24 ft long and sides that are each 17 ft long. the height of an isosceles triangle bisects the base at a right angle, dividing it into two equal lengths. what is the area of this triangular section of the roof? round your final answer to the nearest foot.