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 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.
Side 1 + side 2 + side 3 = perimeter.
Adding up all the three sides of a triangle will give the perimeter of a given triangle
½ × base × height = area.
This formula is useful for calculating the area of a given triangle.