The area of a trapezoid is understood as one-half the sum of the lengths of its parallel bases multiplied by the perpendicular height: . Learners interpret the formula through decomposition or rearrangement into familiar shapes, use whole-number, fractional, or decimal measurements, and distinguish height from the nonparallel sides; the result is expressed in square units, without requiring more advanced generalizations.
A trapezoid has two parallel sides, called the bases. Its area is found by averaging the lengths of the bases and multiplying by the perpendicular height:
The height is the straight-line distance between the parallel bases. It is not necessarily the length of either slanted side.
Example: Find the area of a trapezoid with bases of cm and cm and a height of cm.
Identify the measurements:
Substitute them into the formula:
Add the base lengths:
Multiply:
Therefore, the area of the trapezoid is
The answer is in square centimeters because area measures the amount of surface inside the trapezoid.
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