# What is half of a diameter of a circle called?

Answer: Half of a diameter of a circle is called a radius.

## Geometry: Circles and Their Components

In geometry, a circle is defined by its center and its radius. The radius is half the length of the diameter and is a fundamental concept in understanding the properties of a circle. It’s crucial for calculating the area and circumference of a circle and has practical applications in various fields such as engineering, architecture, and design. Knowing the relationship between the radius and the diameter is essential for solving geometric problems and understanding the spatial aspects of circular shapes.

## FAQ on Geometry: Circles and Their Components

### What is the formula for the area of a circle?

The area of a circle is πr², where r is the radius.

### What is the formula for the circumference of a circle?

The circumference of a circle is 2πr, where r is the radius.

### How do you calculate the diameter of a circle if you know the radius?

The diameter of a circle is 2 times the radius.