In order to calculate the area of circles or hollow cylinders, we need to understand the definition of diameter and radius. A diameter, is the measure of the length of a straight line going across the circle and passing through its center. A radius, is The measure of the distance from the center of a circle to its outside edge. Fun fact, A radius is always half the size of a diameter.
In order to calculate the area of circles or hollow cylinders, we need to understand about diameter and radius.
DIAMETER
The measure of the length of a straight line going across the circle and passing through its center.
RADIUS
The measure of the distance from the center of a circle to its outside edge.
NOTE: The radius is always equal to½ the diameter.