Triangle and Quadrilateral

Triangle and Quadrilateral

Triangle: A triangle is a closed shape with three sides and three angles. The sum of its three angles is always 180 degrees.

Quadrilateral: A quadrilateral is a closed shape with four sides and four angles. The sum of its four angles is always 360 degrees.

Area of Triangle and Quadrilateral

Theorem 1: Parallelograms on the same base and between the same parallel lines are equal in area.

Theorem 2: The area of a triangle is equal to half the area of a parallelogram on the same base and between the same parallel lines.

Theorem 3: Triangles on the same base and between the same parallel lines are equal in area.