Proses A → B → C
\begin{equation*}
\begin{split}
W_1 & = \frac {\text{jumlah sisi sejajar} \times \text{tinggi}}{2} \\\\
W_1 & = \frac {(100 + 300) \times 20}{2} \\\\
W_1 & = 4.000 \text{ J}
\end{split}
\end{equation*}
\begin{equation*}
\begin{split}
W_2 & = \text{panjang} \times \text{lebar} \\\\
W_2 & = 300 \times 20 \\\\
W_2 & = 6.000 \text{ J}
\end{split}
\end{equation*}
Usaha total adalah 4.000 J + 6.000 J = 10.000 J
