Science, Tech, Math › Math Help Kids Calculate the Area and Circumference of Circles Find the Area and Circumference when the Radius is Given Share Flipboard Email Print Math Geometry Math Tutorials Arithmetic Pre Algebra & Algebra Statistics Exponential Decay Functions Worksheets By Grade Resources View More By Deb Russell Math Expert Deb Russell is a school principal and teacher with over 25 years of experience teaching mathematics at all levels. our editorial process Deb Russell Updated February 14, 2018 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. 01 of 02 Circumference Worksheet #1 D. Russell 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. 02 of 02 Circumference Worksheet #2 D. Russell Some teachers require students to memorize formulas, but students do not need to memorize all the formulas. However, we think it's important to remember the value of the constant Pi at 3.14. Even though Pi technically represents an infinite number that starts with 3.14159265358979323846264..., students should remember the base form of Pi which will provide accurate-enough measurements of the circle's area and circumference. In any case, students should be able to understand and apply the formulas to a few questions before using a basic calculator. However, basic calculators should be used once the concept is understood to eliminate the potential for calculation errors. Curriculum varies from state to state, country to country and although this concept is required in the seventh grade in the Common Core Standards, it is wise to check the curriculum to determine what grade these worksheets are suitable for. Continue to test your students with these additional circumferences and areas of circles worksheets: Worksheet 3, Worksheet 4, Worksheet 5, Worksheet 6, Worksheet 7, and Worksheet 8.