each interior angle of a regular polygon is thrice of the exterior polygon. find the number of sides of the polygon.
LectureNotes said each interior angle of a regular polygon is thrice of the exterior polygon. Find the number of sides of the polygon.
Answer: To determine the number of sides of a regular polygon where each interior angle is thrice the measure of each exterior angle, we can follow these steps:
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Understand the relationship between interior and exterior angles:
- For any polygon, the sum of an interior angle and its corresponding exterior angle is always 180^\circ.
- Let the measure of each exterior angle be E.
- Then, the measure of each interior angle will be 3E (since it is given to be thrice the exterior angle).
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Set up the equation:
- Since the interior and exterior angles are supplementary, we have:
E + 3E = 180^\circ - Simplify the equation:
4E = 180^\circ - Solving for E gives:
E = \frac{180^\circ}{4} = 45^\circ
- Since the interior and exterior angles are supplementary, we have:
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Find the number of sides of the polygon:
- The exterior angle of a regular polygon is given by \frac{360^\circ}{n}, where n is the number of sides.
- We know that each exterior angle E = 45^\circ.
- Therefore, we can set up the equation:
\frac{360^\circ}{n} = 45^\circ - Solving for n:
n = \frac{360^\circ}{45^\circ} = 8
Thus, the number of sides of the polygon is \boxed{8}.