Review Multiplying decimals: 3.2 x 5.12 Multiplying fractions and whole numbers: 5 x 2/3
Circles, Pi, & Circumference
The outside of the circle is called circumference The circumference is the distance around the circle.
The midpoint of a circle is center
The line drawn from the centre to the circumference is … radius
The line drawn from one circumference through the centre to another circumference is … radius diameter The diameter cuts the circle in half!
A line that connects one point on the edge of the circle with another point on the circle is called …. chord The chord that passes through the centre of the circle is the diameter.
A segment ie. part of the circumference of the circle is called an... a r c
Parts of the Circle centre radius diameter chord arc
The Definition of Pi Pi, not Pie. 1.The 16 th letter of the Greek alphabet is P or p, corresponding to the roman p. 2. A number, represented by said letter, expressing the ratio of the circumference of a perfect circle to its diameter. The value of pi has been calculated to many millions of decimal places, to no readily apparent pattern.
Pi Equals? π = circumference/diameter ≈ π ≈ 22/7 or 3 and 1/7 We will use ………. (on and on and on)
Use Pi to Find: The area of a circle = πr 2 Circumference of a Circle = πd or 2πr Surface Area of a Sphere, Volume of a Cone, Cylinder and Sphere all are formulas that involve π.
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Find the Circumference of the circle. BACK
Find the circumference using the diameter. BACK
Find the circumference of the circle. BACK
How would you find the diameter of a circle if you were only given the circumference? Find the diameter of a circle that has a circumference of 66. BACK
Videos doperations/pi/ doperations/pi/ cazxAL_tUhttp:// cazxAL_tU 0vTgEEhttp:// 0vTgEE
Find the diameter of the circle below: How to find the diameter given the circumference If you have the circumference: divide the circumference by 3.14 ( ). State the formula Substitute the values for and C.
Find the circumference of the circle below: How to find the radius given the circumference If you have the circumference: divide this by, , 3.14 first to get the diameter. State the formula Substitute the values for and C. Then divide the diameter by 2.
Calculate the missing numbers in the table below using the circumference formula below. What’s the formula? C (cm)d (cm)r (cm) Use 3.14 as an approximation for