Problems on Angle Sum Property of a Polygon

We will learn how to solve the problems on angle sum property of a polygon having 'n' sides. We know, the sum of 3 angles of a triangle is 180°.

1. Find the sum of all the interior angle of a polygon having 29 sides.

Solution:

We know that sum of all the interior angle in a polygon = (n - 2) × 180°

Here, n = 29 

Therefore, the sum of all interior angles = (29 – 2) × 180°

                                                     = 27 × 180°

                                                     = 4860°.


2. If the sum of the measure of the interior angle of polygon is 3240, find the number of sides of the polygon.

Solution:

Let the number of sides of the polygon be n.

The sum of the interior angles = (2n – 4) right angles

But given sum of the interior angles = 3240

Therefore, (2n – 4) × 90° = 3240

           ⇒       2n – 4 = 3240/90

           ⇒       2n – 4 = 36

           ⇒            2n = 36 + 4

           ⇒            2n = 40

           ⇒              n = 40/2

           ⇒              n = 20

Therefore, the number sides of the polygon is 20.


3. Find the sum of interior angles of a decagon.

Solution:

We know, a decagon have 10 sides.

Therefore, n = 10

Sum of interior angles = (2n - 4) × 90°

                              = (2 × 10 - 4) × 90°

                              = (20 - 4) × 90°

                              = 16 × 90°

                              = 1440°

Therefore, the sum of interior angles of a decagon is 1440°.


4. Sum of all interior angles of a polygon is 3060°. How many sides does the polygon have?

Solution:

We know that sum of all the interior angles of a polygon = (n - 2) × 180°

According to the problem, we have

                 (n - 2) ×180 = 3060

               ⇒        (n - 2) = 3060/180         

               ⇒          n – 2 = 17            

               ⇒               n = 17 + 2            

               ⇒               n = 19

Therefore, the polygon have 19 sides.

Polygons

Polygon and its Classification

Terms Related to Polygons

Interior and Exterior of the Polygon

Convex and Concave Polygons

Regular and Irregular Polygon

Number of Triangles Contained in a Polygon

Angle Sum Property of a Polygon

Problems on Angle Sum Property of a Polygon

Sum of the Interior Angles of a Polygon

Sum of the Exterior Angles of a Polygon






7th Grade Math Problems 

8th Grade Math Practice 

From Problems on Angle Sum Property of a Polygon to HOME PAGE




Didn't find what you were looking for? Or want to know more information about Math Only Math. Use this Google Search to find what you need.



Share this page: What’s this?

Recent Articles

  1. What are Parallel Lines in Geometry? | Two Parallel Lines | Examples

    Apr 19, 24 04:39 PM

    Examples of Parallel Lines
    In parallel lines when two lines do not intersect each other at any point even if they are extended to infinity. What are parallel lines in geometry? Two lines which do not intersect each other

    Read More

  2. Perpendicular Lines | What are Perpendicular Lines in Geometry?|Symbol

    Apr 19, 24 04:01 PM

    Perpendicular Lines
    In perpendicular lines when two intersecting lines a and b are said to be perpendicular to each other if one of the angles formed by them is a right angle. In other words, Set Square Set Square If two…

    Read More

  3. Fundamental Geometrical Concepts | Point | Line | Properties of Lines

    Apr 19, 24 01:50 PM

    Point P
    The fundamental geometrical concepts depend on three basic concepts — point, line and plane. The terms cannot be precisely defined. However, the meanings of these terms are explained through examples.

    Read More

  4. What is a Polygon? | Simple Closed Curve | Triangle | Quadrilateral

    Apr 19, 24 01:22 PM

    Square - Polygon
    What is a polygon? A simple closed curve made of three or more line-segments is called a polygon. A polygon has at least three line-segments.

    Read More

  5. Simple Closed Curves | Types of Closed Curves | Collection of Curves

    Apr 18, 24 01:36 AM

    Closed Curves Examples
    In simple closed curves the shapes are closed by line-segments or by a curved line. Triangle, quadrilateral, circle, etc., are examples of closed curves.

    Read More

Polygons - Worksheets

Worksheet on Polygon and its Classification

Worksheet on Interior Angles of a Polygon

Worksheet on Exterior Angles of a Polygon