# What is the area of a circle with diameter 0.64 inches?

Here is the answer to questions like: how to find the area of a circle with diameter 0.64 inches?

### Inputs:

 Radius: or Diameter or Circumference: Unit: inches feet yards miles kilometers meters centimeters millimeters

### Quote of the day...

The area of a circle with diameter 0.64 is 0.3217

### Formulae:

A = πr2 = π(d2)2
A = C2
π = 3.1415
A = area
C = circumference or perimeter
r = radius, d = diameter

### Area of a circle in terms of radius:

Area = π·r2 = 3.14·0.322 = 0.32 square inches(*)

### Area of a circle in terms of diameter:

Area = π·(d2)2 = 3.14·(0.642)2 = 3.14·(0.32)2 = 0.32 square inches(*)

### Area of a circle in terms of circumference:

Area = C2 = 2.012 = 4.04(4·3.14) = 4.0412.56 = 0.32 square inches(*)

(*) 0.32169908772759 inches, exactly or limited to the precision of this calculator (13 decimal places).

Note: for simplicity, the operations above were rounded to 2 decimal places and π was rounded to 3.14.

### A circle of radius = 0.32 or diameter = 0.64 or circumference = 2.011 inches has an area of:

• 2.07548 × 10-10 square kilometer (km²)
• 0.000207548 square meter (m²)
• 2.07548 square centimeter (cm²)
• 207.548 square millimeter (mm²)
• 8.01347 × 10-11 square mile (mi²)
• 0.000248225 square yard (yd²)
• 0.00223403 square foot (ft²)
• 0.3217 square inch (in²)

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.

## Formula for area of a circle

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

A = πr2

A = π(d2)2

### Circle area formula in terms of circumference

A = C2

See below some definitions related to the formulas:

### Circumference

Circumference is the linear distance around the circle edge.

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 = d2.

### 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 = 2·r.

### 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 = Cd . 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 (cm²), if in inches, will get the answer in square inches (in²) and so on ...

Circumference is often misspelled as circunference.

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