91Ó°ÊÓ

A circle is a shape with all points the same distance from its center. This distance is known as the radius. Circles can be found everywhere, from wheels to clock faces.
They have unique properties and many mathematical formulas.

• All points on the edge are equidistant from the center.
• This distance is called the radius.
• The total distance around the circle is called the circumference.

The radius of a circle is the distance from its center to any point on its edge. It’s a key element in circle calculations. Think of the radius as a line connecting the circle’s center to its edge.
Here are some notable points about the radius:

• It is half the diameter of the circle.
• The radius helps in calculating the area and the circumference of the circle.
• In the exercise, the radius given was 10 mm.

The circumference of a circle is the total distance around the outer edge of the circle. We use it to understand how long the boundary of a circle is. It’s important in various real-world scenarios, like finding the length of material needed to wrap around a circular object.
The formula to find the circumference is:
\begin{quote} C = 2 \times \text{π} \times r \text{where} \text{ \(C\) is the circumference and \(r\) is the radius} \text{The value of \(π\) (Pi) is approximately 3.14159.} \text{In the exercise solved:} \text{\(r\) (radius) = 10 mm} \text{Thus: C = 2 × π × 10 mm}\text{Simplifying this we get: C = 20π mm}\text{If you use the approximate value of π, C ≈ 20 × 3.14159 = 62.8318 mm}\text{Hence, the circumference of the circle is about 62.83 mm.}\begin{quote}}

Pi (π) is a special number in mathematics. It’s the ratio of the circumference of any circle to its diameter. Pi is approximately 3.14159 but goes on forever without repeating.
Here are some cool facts about Pi:

• Pi is an irrational number, meaning it cannot be exactly expressed as a simple fraction.
• It is often approximated as 3.14 or 22/7 for calculations.
• Pi is used in various formulas involving circles, such as the circumference and area formulas.