the number of sides in 2 regular polygons is in the ratio 5:4 an the difference between their angles is 9^o. Find the number of sides in the polygon

2 answers

The internal angle each corner of a regular polygon is 180 - 360/n degrees.

Let N be the number of sides of polygon with fewer sides. The other polygon then has 5N/4 sides.

180 - 360/N - [180 - 360*0.8/N] = -9
-360/N + 288/N = -9
72/N = 9
N = 8
The other polygon has 10 sides.
The internal angles are 135 and 144 degrees.
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