Question

The cross section of a metal ingot is a trapezoid. The cross section has an area of 39 square centimeters. The top base of the cross section is 12 centimeters. The length of the bottom base is 2 centimeters greater than the top base. How tall is the metal ingot? Explain

Answer 1

A trapezoid is a polygon of four sides with two parallel sides.

The area of trapezoid is the half sum of the lengths of the paralled sides times the height which is the distance between the parallel sides.

Call b1 and b2 the lengths of the two parallel sides and H the heigth, the formula is [1/2](b1 + b2) H.

We know b1 = 12cm, b2 = 12cm + 2 cm, and the area = 39 cm^2, then we can find H:

39 = [1/2](12 + 14)*H

39 = (13/2)H => H = 2*39 / 13 = 6 cm

Answer: 6 cm