Question 393430
an interior and exterior angle pair are supplementary (add to 180º)


using k as a proportionality constant (fudge factor) ___ 7k + 2k = 180º ___ 9k = 180º ___ k = 20º


so the exterior angle is 2k or 40º


the sum of the exterior angles is 360º ___ 360º / 40º = 9
9 angles AND 9 sides (a nonagon)