SOLUTION: I don't get how to find the area of a circle an d round to the nearest whole number. Will you please help me i will be having a quiz on it 5-31-07 and it is 5-30-07 so please pleas

Question 83875This question is from textbook Harcourt Math
: I don't get how to find the area of a circle an d round to the nearest whole number. Will you please help me i will be having a quiz on it 5-31-07 and it is 5-30-07 so please please please help me. This question is from textbook Harcourt Math

Found 2 solutions by stanbon, josmiceli:
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
find the area of a circle an d round to the nearest whole number.
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Assume you have a circle with a radius = 2.5 inches
Area of a circle = (pi)r^2
Your Circle:
Area = (pi)(2.5)^2
Area = (pi)(6.25)
Area = 19.6346
----------------
Rounding to the nearest whole number
Area = 20 sq. in.
==========================
Chers,
Stan H.
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
The area of a circle is
If you are tol to round your answer to the nearest whole
number, then say your answer is 4.499. This is closer to 4
than it is to 5, so your answer is 4. Say your answer is
4.501. This is closer to 5 than to 4, so your answer is 5.
You have to know what value to use for pi, too. It wmight make
a difference in your answer.
3.141 is 3-place accuracy
3.1415 is 4-place accuracy
3.14159 is 5-place accuracy
You should be told how many decimal places to use on the quiz.
Suppose the radius of a circle is a really big number.
Suppose inches, then

Here, the fewer decimal places you use for pi, the more accuracy you're
going to lose in your answer. I'll try examples, rounding to the nearest
whole number

I'm getting better and better accuracy with more accurate values of pi.
This is only true because r is a large number. I need just as many decimal
places for pi as there are digits in r. After that I won't get
better accuracy rounded to the nearest whole number.

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