Circle – Circumference & Perimeter – Worksheet A The worksheet is provided in four differently-structured formats. Students can use the ‘Circles To Measure’ sheet, or they can measure circular – or more difficult - spherical objects: food packaging; toilet rolls, bottles, batteries, tins, cans, cups, mugs…

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Circumference Investigation START START START START START ① Object 1 1) Pick a circular object. Circumference Investigation 2) From START, mark 3 diameters next to each other on the line. 3) Using a tape measure, measure the circumference of the object. Or roll the object along the line once. 4) Mark the circumference on the line. 5) What conclusions can you make about relationship between the circumference and the diameter of a circle? START Object 1 START Object 2 START Object 3 START Object 4 START Object 5

Circumference = 3….. × Diameter What is the relationship between a circle’s circumference and its diameter? Circumference = 3.1415926535… × Diameter Circumference = 𝜋 × Diameter 𝜋 (Pi) is the relationship between a circle’s diameter and its circumference. Circumference Preview the slide show to check the animations. Diameter 1 Diameter 2 Diameter 3 3.14

Circumference = 𝜋 × Diameter 𝜋 (Pi) is the relationship between a circle’s diameter and its circumference. Circumference Diameter 1 Diameter 2 Diameter 3 3.14

How circular is your head? Plenary How circular is your head? Get your partner to measure the circumference & the diameter (length). Divide the circumference by the diameter. The closer you are to 3.14, the closer it is to a circle! https://www.flickr.com/photos/pss/233842477

Circumference Investigation START START START START START ① Object 1 1) Pick a circular object. Circumference Investigation 2) From START, mark 3 diameters next to each other on the line. 3) Using a tape measure, measure the circumference of the object. Or roll the object along the line once. 4) Mark the circumference on the line. 5) What conclusions can you make about relationship between the circumference and the diameter of a circle? START Object 1 START Object 2 START Object 3 START Object 4 START Object 5

Circumference Investigation START START START START START START ② 1) Pick a circular object. 2) From START, mark 3 diameters next to each other on the line. 3) Using a tape measure, measure the circumference of the object. Or roll the object along the line once. 4) Mark the circumference on the line. 5) What conclusions can you make about relationship between the circumference and the diameter of a circle? START Object 1 START Object 2 START Object 3 START Object 4 START Object 5 START Object 6

③ ③ Circumference Investigation Circumference Investigation c ÷ d 1) Pick a circular object. 1) Pick a circular object. 2) Measure the diameter (d). 2) Measure the diameter (d). 3) Measure the circumference (c). 3) Measure the circumference (c). 4) How many diameters go into the circumference? 4) How many diameters go into the circumference? 5) What conclusion can you make from your investigation? 5) What conclusion can you make from your investigation? Circular Object Diameter (d) Circumference (c) How many diameters in a circumference? c ÷ d Circular Object Diameter (d) Circumference (c) How many diameters in a circumference? c ÷ d

START START START START START START START ④ Object 1 Object 2 Object 3

Circles To Measure

tom@goteachmaths.co.uk Questions? Comments? Suggestions? …or have you found a mistake!? Any feedback would be appreciated . Please feel free to email: tom@goteachmaths.co.uk