Parts of a Circle
In this tutorial students will learn about the characteristics of a circle. The students will be introduced to the following vocabulary words: chord, diameter, radius, center, circumference and pi. Lastly, the students will be introduced to their relationships between these characteristics.
A circle is a set of points that are equidistant from a specific point called the center. A circle is named by its center.
A chord is a line segment that connects 2 points on the circle.
A diameter is a special chord that goes through the center of the circle and connects 2 points on the circle.
A radius is a line segment that connects with the center and a point on the circle.
Circumference is the distance around a circle.
diameter = 2 * radius
radius = diameter/2 or (1/2)*diameter
circumference ≈ 3 * diameter
circumference / diameter ≈ 3 or 22/7
π = circumference / diameter
π = 3.1415926…
π is an irrational number
The circumference divided by the diameter will ALWAYS equal pi, 3.1415926…