Form 1 Unit 14 Lesson 4 – Perimeter and Area of a Parallelogram

Objective

At the end of the lesson, the students should be able to know how to calculate perimeter and area of a parallelogram.

A parallelogram is a quadrilateral in which both pairs of opposite sides are parallel. The perimeter of a parallelogram can be calculated by using a formula.

Perimeter is 2 times the (base + side length)

P = 2 (b +s)

The area of a parallelogram can be calculated by using a formula

Area = base × height

A = b × h

(The height is always perpendicular to the base)

 

Example 1

Find the area of these parallelograms

 

 

 

 

 

 

 

Solution

a)A = h × b                                 b) A = h × b

   =4cm × 7cm                                = 3.5 × 3.1

  =28cm²                                         = 10.85cm²

c)A = h × b

    =3cm × 15cm

    = 45cm²

 

 

 

 

 

 

Example 2

Find the area and perimeter of a parallelogram whose base is 5cm and height 7cm.

Solution

Area of parallelogram = height × base

                              = 7cm × 5cm

                             = 35cm²

Perimeter of the parallelogram = 2(base + height)

                                                = 2 (5 + 7) cm

                                                = 2 × 12cm

                                                = 24cm