Calculate instantly online! Your math assistant to calculate area of circle (surface circle) easily and quickly.
Area for circle
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The following online calculator is an online tool to calculate the area of a circle, based on the radius. The application calculates the circle’s extension using the formula Circle area = π × radius². It allows calculating the circular surface of any element, whether small or large.
Additionally, as an option, you can calculate area of a circumference by also entering the diameter or its circumference.
How does the circle area calculator work?
To calculate the area of a circle follow these steps:
- Enter the value of the radius (r):
- Enter the circle’s radius in the indicated field and select the dimension unit. Optionally, you can use the diameter and perimeter – circumference to calculate the circle’s area.
- Calculate the circle’s surface:
- The area circle calculator will automatically perform the calculation and display the surface according to the selected unit.
How to calculate the area of a circle?
We remind you that the formulas to calculate the area of a circle vary depending on the distance used. Formula of the circle area:
- To calculate the area of a circle with the radius, the formula is Surface = π × radius²
- To calculate the area of a circle with the diameter, the formula is Surface = (π / 4) × diameter²
- To calculate the area of a circle with the perimeter, the formula is Surface = Perimeter² / (4 × π), a simplified option of: π × (Perimeter / (2 × π))²
🟧 Note: The formula to calculate the area of the circle is universal, and remember that the number pi = π is approximately 3.1416
Examples of area calculation in circles:
- If we have a circle with a radius of 5 cm and want to know its extension, we would apply the following calculation: Surface = π × (5 cm)² ≈ 78.54 cm².
- If we know the diameter of a circle, for example, 10 cm, we apply the formula to calculate the circular surface of Surface = (π / 4) × diameter², and we get a result of 78.54 cm².
What units can you use in the calculator to calculate the surface of a circle?
The calculator to obtain the area of a circle allows entering values in the following units:
- Millimeters (mm)
- Centimeters (cm)
- Meters (m)
- Kilometers (km)
- Inches (in)
- Feet (ft)
- Yards (yd)
- Miles (mi)
You can calculate the circumference surface as long as the input values are positive. Additionally, you can change the input and output units to adapt them to the metric or imperial system.
🟧 Note: If you have any questions about this online calculator for a circular area, do not hesitate to contact us from the contact section at the footer.
Frequently asked questions about the area of a circle – FAQ
- What is the formula for the area of a circle?
The formula to calculate the area of a circle is Area = π × radius², where (r) is the radius of the circle and π (pi) is approximately 3.14159.
- How do I calculate the surface of a circle if I know the diameter?
You just have to divide the diameter by 2 to find the radius. Then, apply the area formula: A = π × radius²
- What is the number pi (π) and why is it used in the formula for the area of a circle?
Pi (π) is a mathematical constant that represents the ratio between the circumference of a circle and its diameter. It is used in the area formula because the area of a circle is proportional to the square of its radius, and π is constant in this relationship.
- Can the circle area calculator use different units of measurement?
Yes, as long as you enter all measurements in the same unit of length (for example, meters, centimeters), the calculator can handle any unit.
- How is the perimeter related to the area of a circle?
The perimeter (or circumference) of a circle is calculated with P = 2 × π × r. The relationship between the perimeter and the area is that the area is the square of the radius multiplied by π, while the perimeter is directly proportional to the radius.
- How do I calculate the area of a quarter circle?
To calculate the surface of a quarter circle, divide the area of the full circle by 4.
- Is it necessary to know the radius to calculate the area of a circle?
Yes, the radius is essential to calculate the area using the standard formula of Area = π × r². If you know the diameter, you can find the radius by dividing it by 2.
- How does a change in the radius affect the area of a circle?
The area of a circle increases with the square of the radius. If the radius is doubled, the area quadruples; if it is halved, the area is reduced to a quarter.
- How can the circle area calculator be used in daily life?
It can be used to calculate areas of circular gardens, pizzas, pools, or any circular object for planning, design, or material purchase.
- Is there a way to calculate the area of a circle without a calculator?
Yes, you can do it manually using the formula Surface = π × r² with an approximation of π (for example, 3.14) and performing basic mathematical operations.
