Add the areas of the triangle and the rectangle.

Area of the triangle: $\displaystyle{A}={\left(\frac{{1}}{{2}}\right)}\cdot{20}\cdot{15}={150}\usepackage{cmbright}\Huge\$

Area of the rectangle: $\displaystyle{A}={25}\cdot{2}={50}\usepackage{cmbright}\Huge\$

The total area of the figure is $\displaystyle{150}+{50}={200}\usepackage{cmbright}\Huge\$ square millimeters.