- #1
chops369
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Homework Statement
What is the approximate uncertainty in the area of a circle of radius 5.3 * 104 cm? Express your answer using one significant figure.
Homework Equations
A = pi*r2
The Attempt at a Solution
Using the given radius, I found the area to be 8.8 * 109 cm2.
And since the uncertainty is not given, I'm assuming that it's 0.1 * 104 cm.
Using this, the upper limit for the radius is 5.4 * 104 cm, which makes the upper limit for the area 9.2 * 109 cm2.
Subtracting 9.2 - 8.8 = 0.4 * 109 cm2. 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?