 Polygons - Orchids The International School
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Polygons

• 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.

Types of Polygons

There are two types of polygons:

• Regular Polygon
• Irregular polygon

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. Irregular Polygon:

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

Names of polygon  Triangles

• 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° Types of triangles

• 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

• 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

• 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°. Diagonals

• The line segments that join the opposite vertices is called the diagonal.
• Fun facts: Did you know:  • -