A **polygon shape** is a 2d shape that contains straight lines. Here students will learn about polygons.

In this learning concept, the students will also learn to

- Classify the types of polygons.
- Identify a regular polygon and an irregular polygon.
- Distinguish the different regular polygon shapes.
- Choose examples of polygons and the number of diagonals in a polygon.

Each concept is explained to class 5 maths students using illustrations, examples, and mind maps. Students can assess their learning by solving the two printable worksheets given at the page’s end.

Download the **polygon shapes worksheet** for class 5 and check the solutions to the polygon shapes question for class 5 provided in PDF format.

- A polygon is defined as a two-dimension closed figure formed by joining three or more straight lines.
- Few examples of polygons are:
- Every polygon is a closed figure but not every closed figure is a polygon.
- Look into the figures below:
- Each figure is a closed figure but not every side is made up of straight lines. Therefore, these are not polygons.

There are two types of polygons:

- Regular Polygon
- Irregular polygon

**What Is a Regular Polygon?**

A polygon is said to be a regular polygon if all its side is of equal length and all the angles are equal.

**What Is an Irregular Polygon?**

A polygon is said to be an irregular polygon if all its sides and angles are unequal.

** Polygonal Shape Names**

**Triangle Polygon**

- A triangle is a three-sided closed figure.
- The three-line segments that join to make a triangle is called the sides of the triangle.
- The point where the line segments meet each other is called the vertices of the triangle.
- The angle formed at the vertices of the triangle is called the angles of the triangles.
- The sum of the angles of a triangle is equal to 180°.
- A triangle has 3 vertices, 3 sides, and 3 angles.
- In the figure above ABC is the triangle.
- Sides of the triangle = AB, AC, and BC
- Vertices of the triangle = A, B, and C.
- Angles of the triangle = ∠A, ∠B, and ∠C.
- ∠A + ∠B + ∠C = 180°

- Equilateral triangle
- Isosceles triangle
- Scalene triangle

**Equilateral Triangle**

- In an equilateral triangle, each angle and the length of each side of the triangle are equal.
- Each angle of an equilateral triangle is equal to 60°.
- An equilateral triangle is also called a regular triangle.
- Triangle ABC,
- Side: AB = BC = AC
- Vertices: A, B, and C
- Angles: ∠A = ∠B = ∠C = 60°

**Isosceles Triangle**

- In an isosceles triangle, two angles and the length of two sides of the triangle are equal.
- Triangle AOB,
- Side: AO, AB, OB and AO = AB
- Vertices: A, O and B
- Angles: ∠O = ∠B and ∠A +∠O + ∠B = 180°

**Scalene Triangle**

- In a scalene triangle every angle and side of the triangle are unequal.
- Triangle ABC,
- Side: AB ≠ AC ≠ BC
- Vertices: A, B and C
- Angles: ∠A ≠ ∠B ≠ C and ∠A +∠B + ∠C = 180°

** Square Polygon**

- A square is a four-side closed.
- It is made of two equal triangles.
- It is also known as a regular quadrilateral.
- It has 4 equal sides and the opposite sides are parallel to each other.
- It has 4 vertices.
- It has 4 interior angles and each interior angle of a square is equal to 90°.
- In the above figure, ABCD is a square.
- Side: AB = BC = CD = AB
- Vertices: A, B, C, and D.
- Angles: ∠A = ∠B = ∠C = ∠D = 90°.
- Sum of the angle of the square is 360°.

**Rectangle Polygon**

- A rectangle is a four-side closed.
- It is made of two equal triangles.
- It has 4 sides and the opposite sides are parallel and equal to each other.
- It has 4 vertices.
- It has 4 interior angles and each interior angle of a rectangle is equal to 90°.
- In the above figure, ABCD is a rectangle.
- Side: AB = CD and AD = BC
- Vertices: A, B, C, and D.
- Angles: ∠A = ∠B = ∠C = ∠D = 90°.
- Sum of the angle of the square is 360°.

**Number of Diagonals in a Polygon**

- The line segments that join the opposite vertices is called the diagonal.

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