Rectangle

Area of rectangle = length x breadth = l x b

Perimeter of rectangle = 2 X (length + breadth)

Square

Area of Square = length X length

Periphery of square = 4 X length

Circle

(a) Diameter of circle = 2 X Radius

(b) Circumference or perimeter of circle=2 лr, where r is radius of circle.

(c) Area of circle = лr^2 , where r is radius of circle

(d) Value of л = 22/7

Triangle

Area of Triangle = (Base x Perpendicular) /2

Perimeter of Triangle = Sum of the length of its all three sides.

Right Angle Triangle = A triangle which has one angle 900 is called right angle triangle.

Pythagoras Theorem: In a right angle triangle “square of hypotenuse is equal to the sum of squares of

other two sides.”

From the given figure:

(AB)^2 + (BC)^2 = (AC)^2

Example 1. A rectangular field has 30-meter length and 20-meter breadth. What is the area of this field?

Answer: 600 Square meter.

Area of rectangle = length X breadth

Area of field = 30 X 20 = 600 Square meter.

Example 2. Find the area of a square which has one side of 3 meter?

Answer: 9 Square meter

Area of square = 3 X 3 = 9 Square meter

Example 3. Length of the base of a triangle is 10 Cm and perpendicular is 12 Cm. What is the area

of this triangle?

Answer: 60 Square Cm

Area of Triangle = (Base X Perpendicular)/2

Area = (10 X 12)/2 = 60 Square Cm

Example 4. If the radius of a circle is 10 cm, what will be the length of its diameter?

Answer: 20 Cm

Diameter = 2 X Radius = 2 X 10 = 20 cm.

Example 5.Radius of a circle is 7 cm. What is the area and circumference of this circle?

Answer: 154 Square Cm and 44 Cm

Area of a circle = лr^2 and circumference = 2лr

Area = л (7)^2= (22/7) X 7 X 7 = 22 X 7 = 154 Square Cm

Circumference = 2лr = 2 X (22/7) X 7 = 44 Cm