The center angles of this figure must sum 360°. Since we have 5 equal divisions:
[tex]a=\frac{360}{5}=72\~[/tex]
Now, the angles inside a triangle must always sum 180°. We have a triangle with an angle "a", and two equal angles "x/2".
[tex]\begin{gathered} a+x=180 \\ 72+x=180 \\ x=180-72=108 \\ x=108 \end{gathered}[/tex]
