About All Circle Formulas
Let us first define a circle before studying all of the circle formulas. A circle is defined as a group of points in a plane that are all at the same distance from a fixed point. The fixed point is known as the circle's centre. The radius of a circle is the distance between its centre and its circumference. Let's look at some examples of circle formulas that have been solved.
Important Terms of a Circle
Before learning the formulas, students should understand the basic parts of a circle:
Radius (r): Distance from the centre to the boundary
Diameter (d): A straight line passing through the centre of the circle
Circumference: The boundary or perimeter of the circle
Area: The space inside the circle
The diameter is always twice the radius.
d=2r
What Are All Circle Formulas?
All circle formulas can be used to compute parameters such as area, circumference, and radius of a circle. Different circle formulas for calculating various parameters of a given circle are as follows:
Diameter of Circle, D = 2r
Circumference of Circle, C = 2 π r
Area of a Circle, A = π r2
Where r is the radius of the circle
d is the diameter of the circle
c is the circumference of the circle
All Circle Formulas in One Place. The collection of all circle formulas for easy calculations for a circle with radius 'r' is provided below.
| Parameters | Circle Formulas |
| Diameter of a circle formula | D = 2 r |
| Circumference of a circle formula | C = 2 π r |
| Area of a circle formula | A = π r2 |
Solved Example of Circle Formulas
Example 1: Calculate the size of a circular park with a radius of 200 metres.
Solution:
To locate A park area.
Given: Radius of park = 200 m
Using the area of a circle formula, we have
Area of a Circle = π r2
= π × 2002
= π × 40000
Example 2: Determine the radius of a circle with a circumference of 100 in using the perimeter of a circle formula.
Solution:
To find: Circular radius
Given: Circumference = 100 in using the perimeter of a circle formula,
The perimeter of the circle or circumference = 2 π r
2 π r = 100
2 × 22/7 × r = 100
r = 100 × 7 / 44
r = 15.909 inches
Answer: The circle's radius = 15.909 in
Example 3: A circle's radius is 8 inches. Calculate the circumference of the circle using the circle formula.
Solution:
Circumference of the circle
Given: r = 8in
The perimeter of a circle = 2 π r
C = 2 × (22/7) × (8)
Answer: The circumference of a circle is 50.28 inches.
What is the perimeter of a Semi-Circle Formula?
Because the circumference of a semicircle is half that of a full circle, the formula is 1/2 (2π r) = π r units.
Get the List of Maths formulas.
Importance of Circle Formulas
Circle formulas are useful in solving geometry problems, calculating distances, designing wheels, clocks, rings, pipes, and many real-life objects. Students also use these formulas in school exams and competitive mathematics tests. Practising circle formulas regularly improves problem-solving speed and accuracy. Understanding how to apply these formulas correctly helps students build a strong foundation in geometry.
Conclusion
All circle formulas are essential for understanding geometry and measurement concepts. From finding the circumference to calculating the area, these formulas make mathematical calculations simple and accurate. Learning and practising circle formulas regularly helps students perform better in mathematics and apply geometry in practical situations.
FAQs on All Circle Formulas
While using the circle formula, you will find the diameter (D) in the formula. The diameter of a circle formula is defined as twice the radius.
Therefore,
D = 2r, where r is the radius of a circle.
The perimeter of the circle formula is =2 π r
where 'r' is radius and π is a constant with value (π = 3.14 or 22/7).
As you know, the circumference of the circle formula is = 2 π r.
If we know the value of the circumference of the circle, substituting the value in the formula, we can calculate the radius, 'r'.
r = (circumference of circle)/ 2 π.