Answer:
118.18 mm^2
Step-by-step explanation:
Sides a and b form angle C, so the information given is a side-angle-side (SAS) problem.
Use the formula [tex]A=\frac{1}{2}ab\sin{C}[/tex].
[tex]A=\frac{1}{2}(12)(20)\sin{80^\circ} \approx 118.18 \rm \,mm^2[/tex]
