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Big Ideas Math: Modeling Real Life, Grade 8

BI

Big Ideas Math: Modeling Real Life, Grade 8 View details

Chapter Review

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Exercise 18 Page 132

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

1980^(∘)

Practice makes perfect

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.

Here, we want to find the sum of the interior angle measures of the given polygon. This polygon has 13 sides so it is a 13-gon.

To find the sum of the measures of the interior angles of a 13-gon, we will substitute 13 for n in the expression.

(n-2)180

n= 13

( 13-2)180

▼

Evaluate

Subtract term

(11)180

Multiply

1980

The sum of the interior angles of a 13-gon is 1980^(∘).

Subchapter links

1 Parallel Lines and Transversals p.131

2 Angles of Triangles p.132

3 Angles of Polygons p.132-133

4 Using Similar Triangles p.133