Solution
Here base of triangle $=7.5 \mathrm{~cm}$, height of triangle $=4 \mathrm{~cm}$
Area of triangle $=\frac{1}{2} \times$ base $\times$ height
$$
\begin{array}{l}
=\frac{1}{2} \times(7.5 \mathrm{~cm}) \times 4 \mathrm{~cm} \\
=15 \mathrm{~cm}^{2}
\end{array}
$$