Table of Contents

- 1 What is the area of a 45 diameter circle?
- 2 What is the area of a 16mm circle?
- 3 What is the area of a 40 diameter circle?
- 4 What is the area of a 12 inch circle?
- 5 What is the area of a 17mm circle?
- 6 What is the area of a 20mm circle?
- 7 What is the radius of a circle with a circumference of 2 pi centimeters?
- 8 What is the area of a 2 cm circle?
- 9 How to calculate the area of a circle?
- 10 How is the diameter of a circle determined?
- 11 Is the radius of a circle a real number?

## What is the area of a 45 diameter circle?

What is the area of a circle with diameter 45 inches?

Result: The area of a circle with diameter 45 is 1590 | |
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Formulae: | |

r = 22.5 d = 45 C = 141 | A = πr2 = π(d2)2 A = C24π π = 3.1415 A = area C = circumference or perimeter r = radius, d = diameter |

## What is the area of a 16mm circle?

0.311706 square inches (in²)

**What is the radius of a 45 cm circle?**

What is the area of a circle with radius 45 cm?

Result: The area of a circle with radius 45 is 6362 | |
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Formulae: | |

r = 45 d = 90 C = 283 | A = πr2 = π(d2)2 A = C24π π = 3.1415 A = area C = circumference or perimeter r = radius, d = diameter |

### What is the area of a 40 diameter circle?

The area of a circle is equal to π⋅r2 . If your diameter is 40m, then your radius must be 20m, as the radius of a circle is always half of the diameter. With this equation, you need to multiply π by 202 . Since 202=400 , your equation will be π⋅400 , or π400 .

### What is the area of a 12 inch circle?

Circumference & Areas

Size in Inches | Circumference Inches | Area in Square Inches |
---|---|---|

12 | 37.700 | 144.000 |

12 1/4 | 38.480 | 150.060 |

12 1/2 | 39.270 | 156.250 |

12 3/4 | 40.060 | 162.560 |

**What is area formula?**

Perimeter, Area, and Volume

Table 2. Area Formulas | ||
---|---|---|

Shape | Formula | Variables |

Square | A=s2 | s is the length of the side of the square. |

Rectangle | A=LW | L and W are the lengths of the rectangle’s sides (length and width). |

Triangle | A=12bh | b and h are the base and height |

## What is the area of a 17mm circle?

0.351851 square inches (in²)

## What is the area of a 20mm circle?

Using the formula A=pi*r^2 to find the area. This gives the answer as 100pi mm^2 or 314.2 mm^2.

**What is the π?**

Succinctly, pi—which is written as the Greek letter for p, or π—is the ratio of the circumference of any circle to the diameter of that circle. Regardless of the circle’s size, this ratio will always equal pi. In decimal form, the value of pi is approximately 3.14.

### What is the radius of a circle with a circumference of 2 pi centimeters?

plug in 2 centimeters for r in the formula. So we have (2)(π)(2 cm) which is equal to 4π cm.

### What is the area of a 2 cm circle?

The area of the circle is 4π or 12.5663706143591721…

**What is the area of 8 cm circle?**

The area of a circle is equal to Pi π times the radius r squared. Substitute in the value of the radius r=8 into the formula for the area of a circle. Pi π is approximately equal to 3.14 .

## How to calculate the area of a circle?

Area of a circle = π * r 2. Area of a circle diameter. The diameter of a circle calculator uses the following equation: Area of a circle = π * (d/2) 2. Where: π is approximately equal to 3.14. It doesn’t matter whether you want to find the area of a circle using diameter or radius – you’ll need to use this constant in almost every case.

## How is the diameter of a circle determined?

The diameter of a circle is the length of a straight line drawn between two points on a circle where the line also passes through the centre of a circle, or any two points on the circle as long as they are exactly 180 degrees apart. This is the area contained within a circle with the specified diameter.

**What do you call the perimeter of a circle?**

The distance around a circle is called the perimeter or circumference of the circle. It is usually denoted by C C . If all vertices of a polygon belong on a circle, then the polygon is called inscribed. If all sides of a polygon are tangent to a circle, then the polygon is called circumscribed.

### Is the radius of a circle a real number?

A set of points in a plane equally distanced from a given point O O is a circle. The point O O is called the center of the circle. The distance from the center of a circle to any point on the circle is called the radius of this circle.A radius of a circle must be a positive real number.