Using the formula C = 2πr calculate the circumference of circles to 2 decimal places
Home / 8th grade / Geometry & measures / Measures of 2D shapes / Circumference of circles
Given the radius or diameter of a circle, we can calculate the circumference.
Given a radius r, the circumference of a circle is calculated as:
Circumference = 2 x π x Radius
Given a diameter d, the circumference of a circle is calculated as:
Circumference = π x Diameter
For instance, if we have a circle with a radius of 1 mm, the circumference C to two decimal places will be:
C = 2 x 3.14 x 1 = 6.28 mm
If we have a circle with a diameter of 12 cm, the circumference C to two decimal places will be:
C = 3.14 x 12 = 37.70 cm
Below is a table showing the first 6 question answer pairs for the topic "Circumference of circles" as used in the lessons for this topic. Our games and tests for the topic use these 6 items plus 10 additional question answer pairs.
The topic "Circumference of circles" is in the category Geometry & measures for 8th grade (ages 13 to 14).
Home / 8th grade / Geometry & measures / Measures of 2D shapes / Circumference of circles
Each of our math topics for secondary are made up of between 6 and 20 question and answer pairs (both the written form and a robot voice speaking those questions and answers). Each topic can be used with all the activities on the site.
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