We need to find angle a in the figure.
We know that:
x = 9.342 inches
y = 6.692 inches
z = 2.952 inches
We can do so by finding the legs in the following triangle:
The adjacent leg is x. And the opposite leg is found by subtracting z from y, and then dividing the result by two (assuming the figure is symmetric):
![(y-z)/(2)](https://img.qammunity.org/2023/formulas/mathematics/college/fh3jvaflxpzyikv6doaard3a3zet4mpd5s.png)
Thus, we have:
![\begin{gathered} \sin a=\frac{\text{ opposite leg}}{\text{ adjacent leg}} \\ \\ \sin a=((y-z)/(2))/(x) \\ \\ \sin a=((6.692-2.952)/(2))/(9.342) \\ \\ \sin a=(1.87)/(9.342) \\ \\ a=\arcsin\left((1.87)/(9.342)\right) \\ \\ a\cong11.55\degree \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/x52jvl7hv6xlf4uncawxn9ea1zlysikfyk.png)