(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

What is the approximate uncertainty in the area of a circle of radius 5.3 * 10^{4}cm?Express your answer using one significant figure.

2. Relevant equations

A = pi*r^{2}

3. The attempt at a solution

Using the given radius, I found the area to be 8.8 * 10^{9}cm^{2}.

And since the uncertainty is not given, I'm assuming that it's 0.1 * 10^{4}cm.

Using this, the upper limit for the radius is 5.4 * 10^{4}cm, which makes the upper limit for the area 9.2 * 10^{9}cm^{2}.

Subtracting 9.2 - 8.8 = 0.4 * 10^{9}cm^{2}. But this is apparently not the correct answer, and I can't figure out why. Unless I'm forgetting some fundamental aspect of significant figures, the only other way I can express this in one sig fig is to write out the actual number, i.e. 400000000; but this is also incorrect.

What am I doing wrong?

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# Homework Help: Approximate uncertainty in area of circle

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