Learn Class 11 Math - Triangles

Triangles can be defined as a plane figure which has three straight sides and also three angles made by the intersection of these three sides.

Elements of a triangle include the vertices, sides and the angles of a triangle.

Angles of a Triangle

Angles of a triangle can be defined as the angles secured or marked by the intersection of two adjacent sides internally.

All the three angles of a triangle add up together to make 180° internally.

Types of Triangle

• Equilateral triangle: they can be defined as triangles with all the three sides and the angles equal to each other. Each angle is 60° in case of equilateral triangles.
• Right angle triangle: they can be defined as the triangles which have at least one angle equal to 90°
• Scalene triangles: These triangles have all the three sides and the angles which are not equal to each other.
• Isosceles triangle: A triangle of this type has at least two sides that are not equal to each other. Therefore, the angles adjacent to those two sides are also equal.

Perimeter:

Side 1 + side 2 + side 3 = perimeter.

Adding up all the three sides of a triangle will give the perimeter of a given triangle

Area:

½ × base × height = area.

This formula is useful for calculating the area of a given triangle.