 # Revision Notes For CBSE Class 9 Math Chapter -9 Areas of Parallelograms and Triangles

A parallelogram is a quadrilateral with two pairs of parallel sides. The opposite sides of a parallelogram are equal in length & opposite angles are equal in measures. The Area of a parallelogram is given by the formulae:

Area = base × height

A triangle is a plane figure with three straight sides and three angles. The sum of angles of a triangle is equal to 180 degrees and the exterior angles of a triangle are always equal to 360 degrees. In a triangle, the sum of the angles is always greater than the length of the third angle. The area of a triangle is given by the formulae:

½ * base * height.

## Frequently asked Questions on CBSE Class 9 Maths Notes Chapter 9: Areas of Parallelograms and Triangles

### What is a ‘Parallelogram’?

A quadrilateral with opposite sides parallel and equal is called as a Parallelogram.

### What are the uses of ‘Triangles’?

Triangles are used in supporting the structure of the bridges because they evenly distribute the weight without changing the proportions. This is just one example where triangles are used.

### What is the meaning of a ‘Formula’?

The formula is a fact or a rule written with mathematical symbols.