M5G2 – Students will understand the relationship of the circumference of a circle, its diameter, and pi (pi ≈ 3.14)
A circle is a closed plane figure with all points an equal distance from the center.. A
. A B. B Circumference – distance around a circle. Center – Point A Diameter – a line segment that passes through the center of the circle with its endpoints on the circle. Radius – a line segment with one endpoint at the center and the other on the circle. Chord – a line segment with both endpoints on the circle... C D.. F E
Your Task *You are going to find the circumference and the diameter of circular objects. *You will determine the relationship between the circumference and the diameter. Which is larger? Which is smaller? How much larger? Smaller?
Steps to follow Use the tape measure to measure around the circular object. (Round to nearest cm.) THIS IS THE CIRCUMFERENCE (C). Use the tape measure to measure the diameter. This is the distance across the middle through the center point. THIS IS THE DIAMETER (d). Use a calculator to divide the circumference by the diameter ( ). Record all results on the record sheet.
Let’s Discuss Each time you divided the circumference by the diameter, your answer was about…… So that means???? What is the relationship between the circumference and the diameter?
Using the Vocabulary The relationship between the circumference and the diameter ( ) is call pi. The symbol for pi is: ≈ 3.14
The circumference is about 3 times greater than the diameter of a circle. What operation would you choose to find the circumference if you know the diameter? Yes, Multiplication! d = 2” What is the approximate circumference of this cookie?
The diameter is about three times less than the circumference. What operation would you choose to find the diameter if you know the circumference? Yes, Division!! C = 9” What is the approximate diameter of this cookie?