Tracker

# Parts of Circle

In a circle, **every point on the circle is at the same distance from the center point.**

The center point helps in recognizing the circle.

As you can probably guess from the name, a circle with center O.

The **radius** of a circle is **a line segment that goes from the center point to a point on the circle. It is generally represented as 'r'.**

**A circle has many radii (that's the plural of radius) as you can draw many different lines from the center point to a point on the circle. Each radius is of same length.**

In this picture, **each radius (MN, MO, MP) has the same length** because the distance from the center point to the circle is always the same throughout the circle.

The **diameter** of circle is **a line segment that goes all the way across a circle through the center point. It is the longest distance across the circle as it passes through the centre. It is represented as 'd'.**

**A circle actually has many diameters since you can draw many different lines through the center of the circle. Each diameter, however, has the same length.**

In this picture, **each diameter (MN, MO, MP) has the same length** because all diameters of a circle have the same length, this being twice the **radius**.

So, diameter = 2 x radius

or d = 2 x r

The **circumference** of a circle is the **distance around the outer edge of the circle**. It is really a fancy name for the **perimeter of the circle**.

Circumference = 2 x x r where = 3.14

If you were to run around a circular track, the distance you ran would be the **circumference of the circular track.**

A **chord** is any line segment that **connects any two points on the circle**.

Since the diameter connects two points on the circle, it is also a chord. It is the largest chord in the circle because it goes all the way across through the center.

Every diameter is chord but every chord is not a diameter.

An **arc** is **any connected part of the circle.**

An arc is a segment or a part of the circumference of the circle. It is always curved since circles are curved.

**Example 1**

**Identify the different parts of the circle.**

In this picture,

- Point
**B**is the**center point**of the circle. **AB**is a**radius**because it start from the center**B**to a point**A**on the circle.**DC**is a**diameter**because it goes all the way across the circle through the center**B**.**DC**and**DE**are the**chords**since it connects two points on the circle.**DE**is**NOT a diameter**because it does not go through the center.- The distance all the way around the circle is always the
**circumference.** **AC**is an**arc**because it is a connected part of the circle.

**Various parts of a circle**

**1. Center point**

**center of the circle**.

**Every point on the circle**is at the

**same distance from the center**.

**2. Diameter**

**line segment**that goes

**all the way across a circle through the center point**.

**3. Radius**

**line segment**that goes from the

**center point to a point on the circle**. Thus, it goes halfway through the circle.

**4. Circumference**

**distance around the outer edge of the circle**.

**5. Chord**

**line segment**that connects any

**two points on the circle**.

**6. Arc**

**Any connected part**of the circle.