# How do you name a circle?

Category:
science
space and astronomy

A

**circle**is**named**by its center. Thus, the**circle**to the right is called**circle**A since its center is at point A. Some real world examples of a**circle**are a wheel, a dinner plate and (the surface of) a coin. The distance across a**circle**through the center is called the diameter.

Furthermore, how do you name parts of a circle?

**Important Circle Parts**

- Radius: The distance from the center of the circle to its outer rim.
- Chord: A line segment whose endpoints are on a circle.
- Diameter: A chord that passes through the center of the circle.
- Secant: A line that intersects a circle in two points.

Term | Definition |
---|---|

concentric circles | Two or more circles that have the same center, but different radii. |

congruent circles | Two or more circles with the same radius, but different centers. |

Subsequently, one may also ask, how do you name concentric circles?

To **name** a **circle**, we use the **name** of the center. Since **concentric circles** have the same center, you may wonder **how to name concentric circles**. You may use the radii to that end! For example, to **name** the big **circle**, you could say **circle** with center A and radius Y.

The circumference = π x the diameter of the **circle** (Pi multiplied by the diameter of the **circle**). Simply divide the circumference by π and you will have the length of the diameter. The diameter is just the radius times two, so divide the diameter by two and you will have the radius of the **circle**!