Circumference and Area of a Circle – GCSE Maths

Introduction

  • Circle is very important shape in Geometry. Since it is used in various fields its study is important.
  • Understanding the concepts of Area and Circumference of a Circle is crucial as it is applied in real life like Construction and even in our daily life measurements. Some of them are –

Three circular objects representing real-life examples of circumference and area of a circle – a fan blade, a circular irrigation field, and a magnifying glass.

Circumference of A Circle

  • The Perimeter of a Circle is Circumference. Basically it is the length of circle’s boundary. It is one-dimensional.
  • Circumference is used to find the length of a track or wheel’s perimeter like problems in real life.
  • We can find Circumference of a Circle using its radius with the help of following formula –

Diagram showing the circumference formulas π × d and 2πr with a circle illustration.

certified Physics and Maths tutorSolved Example

Problem: Find the Circumference of the Circle with radius 10 cm.

Circle with a radius of 10 cm marked from the center to the edge.

Solution: 

Formula:

Step-by-step calculation of the circumference of a circle with radius 10 cm.

Final Answer: 62.8 cm

Area of A Circle

  • The space enclosed by circumference of Circle is called its Area. It is two-dimensional.
  • Used to measure the circular object’s area present in real life.
  • The formula of Area of circle is:

Diagram showing the area formula of a circle as 2πr² with a filled circular shape.

certified Physics and Maths tutorSolved Example

Problem: Find the Area of the Circle with radius 10 cm.

Circle with a radius of 10 cm marked from the center to the edge.

Solution: 

Formula:

Worked example showing how to calculate the area of a circle using the formula πr² with radius 10 cm

Final Answer: 314 cm2

certified Physics and Maths tutorSolved Example

Problem: Find out the Circumference and area of the following circles using there diameters

Two circles labeled (a) and (b) showing diameters of 4 cm and 6 cm for calculating circumference and area.

Solution: 

First we find the radius of the circle:

(b) Diameter = 4 cm

Radius = 4/2 = 2 cm

Worked example calculating the circumference and area of a circle with radius 2 cm.

(b) Diameter = 6cm

Radius = 6/2 = 3 cm

Worked example calculating circumference and area of a circle with radius 3 cm using formulas.

Final Answer: (a) 12.56 cm2 and (b) 28.26 cm2

certified Physics and Maths tutorSolved Example

Problem: Find out the Circumference and area of the circle in terms of π?

Circle with a diameter of 12 cm used to calculate circumference and area.

Solution: 

The diameter of the circle is given using it we can find the circumference:

Worked example showing how to find the circumference of a circle using the diameter formula.

To find the Area we need to find the diameter first, So –

Diameter = 12 cm,

Radius = 12/2 = 6 cm:

Worked example showing how to calculate the area of a circle using the radius formula.

Final Answer: 36π cm2

certified Physics and Maths tutorSolved Example

Problem: Fill in the blanks

Table showing radius, diameter, area, and circumference of circles with missing values to be calculated

Solution: 

(1) The Diameter of the Circle is 20cm, So:

Worked example showing how to calculate radius, circumference, and area of a circle from a diameter of 20 cm

(2) The Circumference is given with which we can find the diameter of Circle:

Circumference = 56.52 cm

We can write –

Example showing how to find the diameter of a circle from a given circumference using the formula diameter = circumference ÷ π

From diameter:

Example showing how to calculate the area of a circle from a given diameter using the formula area = πr²

(3) The Radius of the Circle is 5cm, So:

Calculating circumference and area of a circle from a radius of 5 cm

Final Answer: 

Table showing radius, diameter, area, and circumference of different circles