Date:30/04/2020

Class: JSS 1

Subject: Mathematics

Topic: Plane Shape

__Plane Shape__

Plane shape are shapes with two dimensions. They are formed by intersection of horizontal and vertical lines. Examples are rectangle, square, parallelogram, trapezium, rhombus and so on.

__Using formulae to calculate perimeters__

__Rectangle__

Perimeter of rectangle =2 (L+b)

P=2(L+b)

Where p is the perimeter,

L is the length and b is the breadth

__To calculate length __

Length of rectangle = ^{p}_{/ 2} – breadth

__To calculate breadth__

Breadth of rectangle = ^{p}_{/ 2 }– length

__Example__ 1: A rectangular piece of land measure 57m by 42m. What is the perimeter of the field

__Solution __

P=2(L+b)

P=2(57m +42m)

P=2(99m)

P=2 x99m =198m

Example 2:A rectangle has a perimeter of 52cm. calculate the breadth, if the length is 14cm

Breadth = ^{p}_{/ 2 }– length

b = 52cm / 2- 14cm

b = 26cm – 14cm =12cm

Assignment

- A rectangle has a perimeter of 60m. Find the length of the rectangle if its breadth is (a)10m (b)5m