# Help Kids Calculate the Area and Circumference of Circles

## Find the Area and Circumference when the Radius is Given

In geometry and mathematics, the word circumference is used to describe the measurement of the distance around a circle while radius is used to describe the distance across a circle's length. In the following eight circumference worksheets, students are provided with the radius of each of the circles listed and asked to find the area and circumference in inches.

Fortunately, each of these printable PDFs of circumference worksheets comes with a second page that has the answers to all of these questions so that students may check the validity of their work—however, it's important for teachers to make sure they don't give the sheet with answers out initially!

In order to calculate circumferences, students should be reminded of the formulas mathematicians use to measure the distance around a circle when the length of the radius is known: the circumference of a circle is two times the radius multiplied by Pi, or 3.14. (C = 2πr) In order to find the area of a circle, on the other hand, students must remember that the area is based on Pi multiplied by the radius squared, which is written A = πr2. Use both of these equations to solve the questions on the following eight worksheets.

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## Circumference Worksheet #1

In the common core standards for evaluating mathematics education in students, the following skill is required: Know the formulas for the area and circumference of a circle and use them to solve problems and give an informal derivation of the relationship between the circumference and area of a circle.

In order for students to complete these worksheets, they will need to understand the following vocabulary: area, formula, circle, perimeter, radius, pi and the symbol for pi, and diameter.

Students should have worked with simple formulas on perimeter and area of other 2 dimensional shapes and had some experience finding the perimeter of a circle by doing activities like using string to trace the circle and then measuring the string to determine the perimeter of the circle.

There are many calculators that will find the circumference and areas of shapes but it is important for students to be able to understand the concepts and apply the formulas before moving to the calculator.

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