The interior angles of a square have the same value. Each of them are equal to 90 degrees. The interior angles of an equilateral triangle have also the same value and are equal to 60.
Therefore:
The measure of the interior angle of the square is 90 and the measure of the interior angle of the equilateral triangle is 60:
[tex]\begin{gathered} m\angle1=90 \\ m\angle2=60 \\ m\angle3=60 \\ m\angle4=90 \\ m\angle5=60 \end{gathered}[/tex]
c.
[tex]m\angle1+m\angle2+m\angle3+m\angle4+m\angle5=90+60+60+90+60=360[/tex]
