9.1.1 Developing Formulas for Triangles and Quadrilaterals (continued)
Example 4 Games Application
The perimeter and the area of a trapezoid within a tangram is calculated in this example. The squares of the tangram are given as 1 by 1 cm. To determine the perimeter, the lengths of the bases and sides of the trapezoid must be determined. The length of a diagonal of one of the squares of the tangram is 2, according to the Pythagorean Theorem. The lengths of the sides of the trapezoid are equal to the length of the side of the tangram square (1 cm). Thus, P 22 2 1132 2cm. = + + + = + To determine the area of the trapezoid, substitute the lengths of the bases and the height (one-half the length of a diagonal of a tangram square) into the formula for the area of a trapezoid. The area is found to be 3/2 cm 2 .
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