What is the Difference Between Circumference, Diameter and Radius?

The difference between circumference, diameter, and radius can be summarized as follows:

• Circumference (C): This is the distance around the boundary of a circle. It is the perimeter of the circle and can be calculated using the formula $$C = \pi d$$ or $$C = 2\pi r$$, where $$d$$ is the diameter and $$r$$ is the radius.
• Diameter (d): The diameter is the distance across a circle through the center. It is the longest line that can be drawn in a circle passing through the center. The diameter is twice the radius, so $$2r = d$$.
• Radius (r): The radius is the distance from the center of a circle to any point on the boundary. It is half of the diameter, meaning $$r = \frac{d}{2}$$.

To better understand the relationship between these terms, consider the following analogy: Imagine you have a race track (circumference) that surrounds a central area (center of the circle). The circumference is the distance around the track, while the diameter is the length of the track that goes through the central area. The radius is the distance from the central area to any point on the track.

Comparative Table: Circumference, Diameter vs Radius

Here is a table that summarizes the differences between circumference, diameter, and radius:

To calculate the circumference of a circle using the diameter, you can use the formula $$C = \pi d$$, where C is the circumference, π is the constant pi (approximately 3.14), and d is the diameter of the circle. If you have the radius, you can use the formula $$C = 2\pi r$$, where r is the radius of the circle.

The diameter is the full length of the circle running from the edge, through the midpoint, all the way to the other side. The radius is the length from the midpoint of the circle to the outer edge of the circle.