Answer:
3)  Interior Angle = 90°
  Exterior Angle = 90°
4)  Interior Angle = 140°
  Exterior Angle = 40°
Step-by-step explanation:
A regular polygon is a polygon that has all sides of equal length and all angles of equal measure.
The interior angle of a regular polygon is the angle formed by two adjacent sides within the polygon.
The formula for the interior angle of a regular polygon is:
[tex]\boxed{\begin{minipage}{6cm}\underline{Interior Angle of a Regular Polygon}\\\\Interior Angle $=\dfrac{(n-2)\cdot 180^{\circ}}{n}$\\\\where:\\\phantom{ww}$\bullet$ $n$ is the number of sides.\\ \end{minipage}}[/tex]
The exterior angle of a regular polygon is the angle formed by one side of the polygon and the extension of the adjacent side.
The sum of the exterior angles of any polygon is 360°.
Therefore, the formula for the exterior angle of a regular polygon is:
[tex]\boxed{\begin{minipage}{6cm}\underline{Exterior Angle of a Regular Polygon}\\\\Exterior Angle $=\dfrac{360^{\circ}}{n}$\\\\where:\\\phantom{ww}$\bullet$ $n$ is the number of sides.\\ \end{minipage}}[/tex]
Question 3
The given regular polygon has 4 sides.
Therefore substitute n = 4 into the formulas to find the measure of one interior angle and one exterior angle.
[tex]\boxed{\begin{aligned}\textsf{Interior Angle}&=\dfrac{(4-2)\cdot 180^{\circ}}{4}\\\\&=\dfrac{2\cdot 180^{\circ}}{4}\\\\&=\dfrac{360^{\circ}}{4}\\\\&=90^{\circ}\end{aligned}}[/tex]
[tex]\boxed{\begin{aligned}\textsf{Exterior Angle}&=\dfrac{360^{\circ}}{4}\\\\&=90^{\circ}\end{aligned}}[/tex]
Question 4
The given regular polygon has 9 sides.
Therefore substitute n = 9 into the formulas to find the measure of one interior angle and one exterior angle.
[tex]\boxed{\begin{aligned}\textsf{Interior Angle}&=\dfrac{(9-2)\cdot 180^{\circ}}{9}\\\\&=\dfrac{7\cdot 180^{\circ}}{9}\\\\&=\dfrac{1260^{\circ}}{9}\\\\&=140^{\circ}\end{aligned}}[/tex]
[tex]\boxed{\begin{aligned}\textsf{Exterior Angle}&=\dfrac{360^{\circ}}{9}\\\\&=40^{\circ}\end{aligned}}[/tex]