Finding area of circle using circumference

Relationship between diameter and radius: Diameter of a circle is twice of its radius. Formula: Diameter = 2 x radius Radius = r O r A B d

Pi (π) The ratio of circumference to diameter is constant for all circles. This ratio is called Pi and is written as π. Where π = C = π ⇒ C = πd ⇒ C = 2πr d 22 7

Area of a circle Area of the circle = πr² sq. units The area of a circle is given by the formula Area of the circle = πr² sq. units

Given:- Circumference = 88m To Find:- Area of circle Example 1: The circumference of a circle is 88 m. Find the area of the circle. Solution Given:- Circumference = 88m To Find:- Area of circle We know that Area = πr² Since radius(r) is not given we find radius(r) using Circumference We know that Circumference = 2πr 2 Divide 88 and 44 by 44 r = 2 x 7= 14 cm

Now we have found radius, Lets us now calculate area of circle We know that Area of circle = πr² 2 Divide 14 and 7 by 7 Area = 22 x 2 x 14 = 616 cm2 (Ans)

Given:- Circumference = 132m To Find:- Area of circle Example 1: The circumference of a circle is 132 m. Find the area of the circle. Solution Given:- Circumference = 132m To Find:- Area of circle We know that Area = πr² Since radius(r) is not given we find radius(r) using Circumference We know that Circumference = 2πr 12 Divide 121 and 44 by 11 4 r = 84/4 = 21 cm

Now we have found radius, Lets us now calculate area of circle We know that Area of circle = πr² 3 Divide 21 and 7 by 7 Area = 22 x 3 x 21 = 1386 cm2 (Ans)

Try these The circumference of a circle is 44 m. Find the area of the circle.