Glencoe Math: Course 3, Volume 2
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Glencoe Math: Course 3, Volume 2 View details
4. Polygons and Angles
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Exercise 15 Page 402

The sum of the measures of the interior angles of a polygon is (n-2)180, where n represents the number of sides.

D

Practice makes perfect

We are given a stained glass window in the shape of the following regular polygon.

Regular hexagon
We are asked to find the measure of ∠ H. Let's start by recalling the rule for the sum of the measures of the interior angles of a polygon.

Interior Angle Sum of a Polygon

The sum of the measures of the interior angles of a polygon is (n-2)180, where n represents the number of sides.

To find the measure of one interior angle of a regular hexagon, we will start by finding the sum of its interior angles. Since a hexagon is a polygon with six sides, we will substitute 6 for n in this expression.
(n-2)180
( 6-2)180
Evaluate
(4)180
720
The sum of the interior angles of a hexagon is 720^(∘). Now, recall that a regular polygon is a polygon in which all the angles have the same measure. Therefore, a regular hexagon has 6 angles with the same measure. To find the measure of one angle, we will divide the sum of the angles by 6. Sum of Angles:& 720^(∘) [0.5em] One Angle:& 720/6=120^(∘) Since each interior angle of a regular hexagon has the measure of 120^(∘), the measure of ∠ H is equal to 120^(∘). This means that D is the correct option.