Respuesta :

The sum of measure of exterior angles of a regular polygon is always 360 degree.

Determine the measure of a exterior angle for a regular nonagon.

[tex]\begin{gathered} \angle1=\frac{360}{9} \\ =40 \end{gathered}[/tex]

Determine the measure of exterior angle for a regular pentagon.

[tex]\begin{gathered} \angle2=\frac{360}{5} \\ =72 \end{gathered}[/tex]

The angle RST is equal to sum of exterior angle of nonagon and exterior angle of pentagon. So,

[tex]\begin{gathered} \angle RST=\angle1+\angle2 \\ =72+40 \\ =112 \end{gathered}[/tex]

Thus measure of angle RST is 112 degree.

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