Question

100 points the right answer please the set designer for a play painted some background scenery on a large piece of plywood. He used a 13-foot-long pole to hold the piece of plywood upright, as in the diagram below. What is h, the total height in of the feet of the piece of plywood

13ft 2ft 5ft

Answer 1

14 ft

Explanation:

Focus on the triangle, and temporarily neglect the 2 ft measurement at the top of the triangle. Then the 2 legs of the triangle have lengths h - 2 ft and 5 ft, and the hypotenuse is 13.

Applying the Pythagorean Theorem, we get:

13^2 = (h - 2)^2 + 5^2, or

169 = h^2 - 4h + 4 + 25, or

144 = h^2 - 4h + 4, or

140 = h^2 - 4h, or, finally,

h^2 - 4h - 140 = 0. We must find the value of h.

I graphed this function on a calculator and found that -10 is a zero. Thus, the function factors into (h + 10)(h - 14) = 0, or h = 14.

The total height of the piece of plywood is 14 ft.

Check this: does a right triangle with legs (14 - 2) and 5 have a hypotenuse of 13? Yes.