CLASS-9
AREA & PERIMETER OF PLANE FIGURE

PERIMETER AND AREA OF PLANE FIGURE –

Perimeter –

The perimeter of a plane figure is the length of its boundary, i.e. the sum of its sides. The unit of perimeter is the same as the unit of length.

Area –

The area of a plane figure is the measure of the surface enclosed by its boundary, i.e. the surface enclosed by its sides.

It is measured in square units such as square centimetres or square meters, written or denoted as cm² or m² respectively. In this chapter, we should like to learn the formulae for area & perimeter of triangles and quadrilaterals.

PERIMETER AND AREA OF TRIANGLE –

                              1

i) Area of Triangle =  ---------- X Base X Corresponding Height

                              2

ii) Perimeter of △ ABC = (a + b + c), where a, b, c are the sides of the triangle.