## Elementary Geometry for College Students (6th Edition)

84 $cm^{2}$
The area of triangle whose base has length b and whose corresponding altitude has length h is given by A = $\frac{1}{2}$ bh In triangle ABC base b= 21 cm Height h = 8 cm. A =$\frac{1}{2}$ bh = $\frac{1}{2}$* 21 * 8 = 84 $cm^{2}$