Back to Basics Radius and Diameter Review
To 2 decimal places, find the circumference of a circle with 17 radius.
(Pi = 3.14 in this problem)
Hint: C = 2 pi r
The answer is 106.81.
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2 solutions
Well Rocky, I think in the question, you should clarify that π equals 3 . 1 4 as people might think the number is longer so they get the answer wrong. So can you just check my working out please:
Circumference = 2 π R
The radius is 17.
So the circumference is 17 × 2 which equals 3 4 .
Next we need to work out 3 4 π or as some would say, 3 4 × π which is 3 4 × 3 . 1 4 .
3 . 1 4 × 3 4 _ _ _ _ _ _ 1 0 6 . 7 6
But you say the answer is 1 0 6 . 8 1 .
If you don't believe me, go on google calculator and calculate, 3 . 1 4 × 3 4 .
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Note that π = 3 . 1 4 . It is only approximately 3.14.
We know that,
C = 2 π r
⇒ C = 3 4 × ( 7 2 2 ) ≈ 1 0 6 . 8 1
Thanks! Hope you enjoyed the problem
Using the hint you would know circumference = two pi radius . In other words the radius times two, wich equals the diameter times pi, wich is 3.14 in short, would equal the circumference. Making a circle with a radius of 17 equal to a circumference of 106.81.