What is a Diameter?
Prior to discussing how to calculate diameter from circumference, let us define a diameter. Diameter is a chord or a straight line segment that runs through the center point of any circle and touches two points on the circumference of a circle. It is the longest possible chord of any circle.
Additionally, a circle’s diameter essentially splits the shape in half.
What is a Circumference?
Circumference of a circle or perimeter of a circle is the length of the complete arc of a circle. That is, the circumference would be the length of the circle if it were opened up and straightened out to a line segment.
In addition, circumference is represented by the uppercase letter C and it is measured in terms of units of length like centimeters, meters, or kilometers.
Formula to Calculate Diameter (d) from Circumference (C).
Example 1:
Calculate the diameter of a circle whose C is 154 cm.
Hence, the diameter is 49cm.
Example 2:
Calculate the diameter of a bicycle wheel if its C is 2155 mm.
d = C ÷ π
= 2155 ÷ 3.142
Therefore, the circumference of the wheel is 685.87 mm
Example 3:
Suppose a merry-go-round has a circumference of 78.5 feet. Calculate its diameter.
d = C ÷ π
= 78.5 ÷ 3.142
= 24.98 ft
