Question 1160876: find the area of a circle with diameter 14cm.use the value 3.14 for pie and do not round your answer be sure to include the correct unit in your answer
Answer by solver91311(24713)   (Show Source):
You can put this solution on YOUR website!
The area of a circle is found by squaring the radius and multiplying by  . (, by the way, should be rendered in plain text as "pi" because "pie" is a pastry item with either a fruit or other sweet filling served as a dessert, or a savory filling served as either a main or side dish.)
You were given the diameter, 14 cm, so you need to first compute the radius which is precisely one-half of the diameter, namely 7 cm.
So, 7 cm squared is 49 multiplied by the required approximation for , 3.14, results in 153.86 square centimeters. And this is the answer required by the question.
However, for the question as stated, this answer is absolutely and demonstrably wrong. Here is why: ALL measurements are approximations. You were given 14 cm as a measure of the diameter. But since you were given the approximate measurement to the nearest whole centimeter, you are only guaranteed that the true measurement is in the interval  based on the rules for rounding. Therefore the true measure of the area, based on the given approximation of is in the range
^2 \leq\ A\ <\ 3.14\(\frac{14.5}{2}\)^2)
 square centimeters
Which renders the decimal fraction on the requested answer utterly meaningless. If your instructor had wanted an answer correct to two decimal places s/he should have expressed the original diameter measurement as 14.00 centimeters.
Rule: Never express the FINAL result of a calculation involving measurements to greater precision than the least precise given measurement.
John
My calculator said it, I believe it, that settles it
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