Question

Find the measurement of one angle in a 72-gon

Answer 1

\(\large \begin{array}{rllll}
a&\cdot &n=360\\
\uparrow &&\uparrow \\
\textit{external angle}&&\textit{number of sides}\\
\downarrow&&\downarrow\\
a&\cdot &72=360
\end{array}\)

solve for "a" to get the external angle
if you want the internal angle
keep in mind that internal and external angles are both supplementary angles