Question 1210728: at each vertex of a regular n-gon, the ratio of the interior angle to the exterior angle is 19:1. find the value of n. Answer by ikleyn(54062) (Show Source):
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at each vertex of a regular n-gon, the ratio of the interior angle to the exterior angle is 19:1.
find the value of n.
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Since the n-gon is regular, all the exterior angles are congruent
(just as all interior angles are congruent).
Let the measure of each exterior angle be x.
Then each interior angle measures 19x, according to the problem.
x + 19x = 180 degrees.
20x = 180 degrees
x = 180/20 = 9 degrees.
If n is the number of vertices, then nx = 360 degrees, or
9n = 360 degrees,
n = 360/9 = 40.
ANSWER. The value of n is 40. n = 40.