Question

find the area of the trapezoid.
11 cm
12 cm
21 cm
? cm²

Explanation:

Step1: Recall trapezoid area formula

The formula for the area of a trapezoid is \( A=\frac{(a + b)}{2}\times h \), where \( a \) and \( b \) are the lengths of the two parallel sides (bases), and \( h \) is the height (the perpendicular distance between the bases).

Step2: Identify values of \( a \), \( b \), and \( h \)

From the diagram, \( a = 11\space\text{cm} \), \( b = 21\space\text{cm} \), and \( h = 12\space\text{cm} \).

Step3: Substitute values into the formula

Substitute \( a = 11 \), \( b = 21 \), and \( h = 12 \) into the formula:

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Answer:

\( 192 \)