All You Need to Know About Triangle

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A triangle is a two-dimensional figure polygon, which has 3 sides, 3 edges, and 3 vertices. In Euclidean geometry, a triangle is one of the most important figures. Triangle makes three angles whose sum will be equal to 180 degrees. This article will talk about the area, applications, properties, shape, and perimeter of triangles.


Some of the properties of the triangle are given below:

  1. It has three sides with three angles.
  2. 180 degrees will be the sum of all interior angles.
  3. The Sum of all sides of a triangle is referred to as a perimeter of a triangle. 
  4. The exterior angles of a triangle are always equal to 360 degrees.
  5. The third side is always greater than the sum of the two sides of a triangle.

How to calculate the Perimeter of the Triangle?

A perimeter of a triangle is defined as the total length covered by the boundary of the triangle. For the calculation, we have to add all of its sides. 

Formula to calculate the perimeter of triangle = Sum of All Sides

let PQR is a triangle, where PQ, QR, and RP are the lengths of its sides, then the perimeter of PQR is given by:

Perimeter of triangle = PQ+QR+RP

Area of a Triangle

The area is different from the perimeter of a triangle. The area is the region is covered by the triangle in a 2-D plane. We can calculate the area by knowing the base length and the height of a triangle. It is measured in square units.

Let a triangle have base ‘B’ and height ‘H’ then we can calculate the area of a triangle:


Area = 1/2 × Base × Height

Area = 1/2 ×H×B


Triangles can be classified into two ways

(a) On the basis of angle’s measurement, they are classified into three categories:

  1. Acute Angle Triangle
  2. Right Angle Triangle
  3. Obtuse Angle Triangle

Acute Angled Triangle: A triangle, with all the angles, less than 90°.

Right Angled Triangle: A triangle, of one right angle ie. equal to 90°.

Obtuse Angled Triangle: A triangle, in which any of its one angles more than 90°.

 (b) On the basis of length, they are classified into three categories:

  1. Scalene Triangle
  2. Isosceles Triangle
  3. Equilateral Triangle

Scalene Triangle: A triangle, in which the length of all three sides is different. Because of this, all three angles are also different from each other.

Isosceles Triangle: A triangle, in which two sides have equal length. Because of this, two angles are also equal to each other.

Equilateral Triangle: A triangle, in which has three sides equal to each other. Because of this, all the internal angles are equal.

 All these triangles are different in shape but, the formula to calculate the area and perimeter of the triangle remains the same for all.


Question- Find the perimeter of a triangle with asides 54 m, 64 m, 46 m

Solution- We know the formula of perimeter of triangle = sum of all its sides

= 54 + 64 + 46

= 164 m

Question 1: If XYZ is a triangle where XY = 8cm, YZ = 5cm and ZX = 4cm, then find the perimeter of triangle.

Solution: Given, ABC is a triangle.

XY = 8cm

YZ = 5cm

ZX = 4cm

As we know by the formula, 

Perimeter of triangle = Sum of all three sides

1. P = XY + YZ + ZX

2. P = 8+5+4

3. P = 17cm

Question- Find the perimeter of triangle ABC?

Perimeter of triangle = sum of all sides

= 9+12+5

= 26 m

Moreover, if someone wants to know more about the geometrical pattern of mathematics, then search Cuemath on a google search bar. This online mathematical platform will show unlimited stuff related to angles, shapes, and geometries. It will help to enhance the knowledge and increase the capabilities to recognize any geometrical shapes within a fraction of time.

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