SOLUTION
Given the question in the image, the following are the solution steps to answer the question.
STEP 1: Find the area of a
The shape in a is a parallelogram and the area is given as:
![\begin{gathered} Area=base\cdot height \\ base=20cm \\ height=? \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/stc5y7uc98t7rllgeehjth47vhoqts56od.png)
Find the height using the trigonometric ratios
![\begin{gathered} \theta=60,hypotenuse=10,height=opposite=? \\ Using\text{ SOH} \\ sin60=(height)/(10) \\ height=10\cdot\sin60 \\ height=10\cdot(√(3))/(2)=5√(3) \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/gxaeuxnef086htviurf3f7py0sxqnkpr4z.png)
Area of the figure in a is:
![20\cdot5√(3)=100√(3)cm^2](https://img.qammunity.org/2023/formulas/mathematics/college/wjb8ab2wm613f6866xukum34uf0v8sd5m6.png)