PROPERTIES OF TRIANGLE

In this article, we are going to learn about the simplest form of a polygon, a triangle. All polygons can be divided into triangles, or in other words, they are formed by combining two or more triangles. Thus, understanding the basic properties of a triangle and its types is essential.

There are six types of triangles in total – Isosceles, Scalene, Equilateral, Oblique, Acute, and Right. Based on the classification according to internal angles, there are three types – Equilateral, Isosceles, and Scalene. Whereas, the types of a triangle that are classified according to the length of its side are Right, Acute, and Oblique. Here are the types of triangles:

Based on the Angle	Based on the Sides
Acute Angled Triangle	Equilateral Triangle
Oblique angled Triangle	Scalene Triangle
Right Angle Triangle	Isosceles Triangle

What is a triangle?

As the name suggests, the triangle is a polygon that has three angles. So, when does a closed figure has three angles?

When it has three line segments joined end to end.

Thus, we can say that a triangle is a polygon, which has three sides, three angles, three vertices and the sum of all three angles of any triangle equals 180°.

Types of triangles

Triangles can be classified in 2 major ways:

Classification according to internal angles (Right, Acute, Oblique)
Classification according to the length of its sides (Equilateral, Isosceles, Scalene)

Let’s look into the six types of triangles in detail:

Acute Angled Triangle
Right-Angled Triangle
Oblique Angled Triangle
Scalene Angled Triangle
Isosceles Angled Triangle
Equilateral Angled triangle

PROPERTIES OF TRIANGLE

The sum of all interior angles of any triangle is equal to 180°
The sum of all exterior angles of any triangle is equal to 360°
An exterior angle of a triangle is equal to the sum of its two interior opposite angles
The sum of the lengths of any two sides of a triangle is always greater than the length of the third side
Similarly, the difference between the lengths of any two sides of a triangle is always less than the length of the third side
The side opposite to the smallest interior angle is the shortest side and vice versa.
Similarly, the side opposite to the largest interior angle is the longest side and vice versa.
- In the case of a right-angled triangle, this side is called the hypotenuse
The height of a triangle is equal to the length of the perpendicular dropped from a vertex to its opposite side, and this side is considered the base.