A door height is 6 feet and 6 inches and 36 inches wide. What is the widest piece of sheetrock that will ?t through the door? Round to the nearest inch.

a. 114 in

b. 86 in

c. 85 in

d. 69 in

b. To determine the width of the piece of sheetrock that will ?t through the door, we recognize it to be same to the length of the diagonal of the door frame. If the height of the door is 6 ft 6 in, this is equivalent to 78 inches. Using the Pythagorean theorem, a = 78 and b = 36, we can solve for c. (78)² + (36)² = c². Simplify: 6,084 + 1,296 = c²; 7,380 = c². Take the square root of both sides, c = 86. If you select a, you added 78 + 36. If you select c, you rounded incorrectly. If you select d, you assigned 78 inches as the hypotenuse, c.