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Triangles: Types of Triangles

  A closed structure formed by three intersecting lines is described as a triangle.

   A triangle has three sides, three angles and three vertices A, B, and C.

   A triangle is a polygon with all these properties.

   The three angles of a triangle always sum equal to 180°.

What is Triangle

For example: In triangles ABC, denoted as Types of TrianglesABC. AB,BC and CA are the three sides. anglesAB , anglesBC , anglesCA are three angles. A, B, and C are three vertices

Types of TrianglesABC= anglesAB + anglesBC + anglesCA

Types of TrianglesABC= 600 + 60 + 60

Types of TrianglesABC= 1800

Types of Triangles

There are basically six types of triangle, which is below.

  1. Isosceles
  2. Equilateral
  3. Scalene
  4. Right Triangle
  5. Obtuse
  6. Acute

1.Isosceles Triangles

Isosceles Triangles

In this triangle only two sides are equal and two angles are equal.


Triangle Equilateral

In equilateral, all three sides are equal(AB=BC=CA) and all three angles are equal (anglesAB = anglesBC = anglesCA=600)

3. Scalene

Scalene Triangles

In this type of triangle, there are no sides equal and no equal angles.

4.Right Triangle

Right Triangle

In right triangle, one  angle always 90°.

5.Obtuse Triangle

Obtuse Triangle

In this type of triangle One angle > 90° or more than 90°.

6. Acute Triangle

Acute Triangle

All angles < 90°.

Area of Triangle

Area of Triangle

The area is 1/2 of the base times height.

“b” is the distance along the base
“h” is the height

Area = ½ × b × h

This formula works for all types of triangles.

Example: What is the area of this triangle?

what are the area of triangles






(Note: 100 is the height, not the length of the left-hand side)

Height = h = 100

Base = b = 40

Area = ½ × b × h 

Area = ½ ×40 × 100 = 2000

Area of Triangles: Formulas & more Examples