Lesson 2 - Circumference of a Circle
The objective of this second lesson is to determine how the circumference of the circle is calculated. We shall firstly recap on what we learned in the last lesson as a class and then work in pairs to complete the lesson activity before undertaking the quiz and assessments individually.
RevisionBefore we start the topic for today, let us assess if we can confidently name the parts of the circle we learned about during the last lesson.
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Rolling, rolling, rolling!
Use your mouse to change the diameter of the circle by moving the blue point up and down. The diameter is the green number. Now slide and watch the circle roll the distance of one circumference by moving the black point with your mouse right along the "RollTheCircle" slider. The circumference length is the red number.
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How do you think the distance rolled, i.e. the circumference, compares with the diameter of the circle? Lets try a number of different rolls and input our findings into the spreadsheet below:
Let us try 10 different diameter sizes.
Quiz Time!What did you notice about the blue numbers which appeared? Is there a pattern? Have you figured out how the blue number is calculated? Let us take a short quiz to see how you are going.
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Hopefully you did really well in the quiz but if you didn't quite manage to achieve 100% first time please redo the rolling, rolling, rolling exercise above and try again. If in doubt please ask your teacher or a friend for some assistance.
So what is the blue number? This number of approximately 3.14 is called Pi (not pie) and you will learn more about Pi in Lesson 3. So we have found that we can calculate the circumference of a circle by multiply the circle diameter by Pi.
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Practise Time!Lets put this new knowledge to the test! Please log into your www.sumdog.com account via the button below and complete the allocated tasks.
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Homework and Early Finishers
If you haven't finished the allocated Sumdog activity and assessment during the lesson you will have to complete them both for homework. You are also required to download the worksheet and complete it before the next lesson.
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What did you think of the Lesson? |
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