# How do you find the approximate uncertainty of a circle of radius 3.8x10^4?

how do you find the approximate uncertainty of a circle of radius 3.8x10^4????

## Homework Statement

how do you find the approx uncertainty for a circle with radius 3.8x10^4, i have no idea how to get the final uncertainty of the circle the radius uncertainty is 0.1x10^4

area of a circle is pie*r^2? so that means the area of the circle should be 4.5x10^9 isnt it???

## The Attempt at a Solution

i figured that because there is only one variable that the uncertainty would just be 0.1x10^4, how do you work out the final uncertainty properly?????

Related Introductory Physics Homework Help News on Phys.org

One way to do this that always works is to calculate the area for the minimum and for the
maximum radius to find out what the minimum and maximum values of the area are.

Another way is $f(x+ e) \approx f(x) + e f'(x)$ is e is small. (e is the error)

thanks willem, saved my life =)