The percent error of this length measurement is 1.77%. Here is how you find this error.
First, you have to find how far off your estimate was from the actual correct value. In this case, we can see that the difference was .004 centimeters.
Now, we need to find out what this error is as a percent of the actual measurement. That is a way of showing how badly our estimate was incorrect. We do this by dividing the error (.004) by the correct answer (.225). This gives us a result of .01777.
To make this into a percentage, we multiply that by 100 and we get 1.77%.
The correct value of the length that is being measured is .225 cm.
But during measurement the length is incorrectly measured as .229 cm.
Therefore the absolute error is .229 - .225 = .004 cm. Now we have to remember that the error is expressed as a percentage of the correct length and not as a percentage of incorrect length. So we have to determine what percent of .225 is .004.
0.004 as a percentage of .225 this is equal to (.004 / .225)* 100 = 16/9 % or 1.7778%
((0.229-0.225)/0.225)*100= 1.8% error