The are of the triangle is given as follows:
[tex]\text{Area}=\frac{1}{2}\times base\times perpendicular\text{ height}[/tex]
From the triangle given, we have:
base = 21cm
perpendicular height = 7cm
Thus:
[tex]\text{Area = }\frac{1}{2}\times21\times7=\frac{147}{2}=73.5\text{ square centimeters}[/tex]
