# What is the area of a circle with diameter 10.2 kilometers?

Here is the answer to questions like: how to find the area of a circle with diameter 10.2 kilometers?

Use the this circle area calculator below to find the area of a circle given its diameter, or other parameters. To calculate the area, you just need to enter a positive numeric value in one of the 3 fields of the calculator. You can also see at the bottom of the calculator, the step-by-step solution.

### Area of a Circle Calculator

## Formula for area of a circle

Here a three ways to find the area of a circle (formulas):

### Circle area formula in terms of radius

### Circle area formula in terms of diameter

### Circle area formula in terms of circumference

See below some definitions related to the formulas:

### Circumference

Circumference is the linear distance around the circle edge.

### Radius

The radius of a circle is any of the line segments from its center to its perimeter. The radius is half the diameter or r = ^{d}/_{2}.

### Diameter

The diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. The diameter is twice the radius or d = 2r.

### The Greek letter π

π represents the number Pi which is defined as the ratio of the circumference of a circle to its diameter or π = ^{C} / _{d}. For simplicity, you can use Pi = 3.14 or Pi = 3.1415. Pi is an irrational number. The first 100 digits of Pi are: 3.1415926535 8979323846 2643383279 5028841971 6939937510 5820974944 5923078164 0628620899 8628034825 3421170679 ...

### Note:

If you input the radius in centimeters, you will get the answer in square centimeters (cmÂ²), if in inches, will get the answer in square inches (inÂ²) and so on ...

Circumference is often misspeled as circunference.

You can use our area unit converter to see the results in other units.

## Sample Circle Area Calculations

- Area of a Circle with radius 4.9 yard
- Area of a Circle with circumference 3.5 inches
- Area of a Circle with radius 19.3 meters
- Area of a Circle with radius 17.6 kilometers
- Area of a Circle with radius 19.5 kilometers
- Area of a Circle with diameter 19 units
- Area of a Circle with circumference 10.2 yard
- Area of a Circle with radius 70 centimeters
- Area of a Circle with circumference 16.8 kilometers
- Area of a Circle with diameter 18.4 miles

- Area of a Circle with radius 7.4 feet
- Area of a Circle with diameter 66 mm
- Area of a Circle with circumference 17 pi miles
- Area of a Circle with diameter 4.4 mm
- Area of a Circle with diameter 20 inches
- Area of a Circle with radius 12.6
- Area of a Circle with radius 17.6 centimeters
- Area of a Circle with diameter 4138
- Area of a Circle with diameter 8 mm
- Area of a Circle with radius 6.6

- Area of a Circle with radius 17 meters
- Area of a Circle with circumference 19.3 inches
- Area of a Circle with diameter 17.7 units
- Area of a Circle with radius 19.1 meters
- Area of a Circle with diameter 59 feet
- Area of a Circle with diameter 2.8 feet
- Area of a Circle with circumference 17.7 feet
- Area of a Circle with circumference 12 feet
- Area of a Circle with radius 16 yard
- Area of a Circle with radius 78 meters