How do you find the percent error of the volume of a rectangular prism?

Question

This is a text book question that I think is lacking information. Does anyone know generally how to calculate percentage error.

Answer 1

Let's suppose there is a 1% error in measuring the length, then there is a 3*1 = 3% error in calculating the volume.

Consider a cube of side L +/- 1%
is length = L(1 +/- 0.01)
Volume = L^3 *(1 +/- 0.01)^3
This ranges from 0.9703*L^3 to 1.0303*L^3
So it is approximately L^3 +/- 3%

Answer 2

Here's the formula for calculating percent error:

Find the absolute value of the difference of the experimental value (your answer) and the theoretical value. Divide this answer by the theoretical value and multiply by 100.

Here's an example you can use:

your answer: 5
theoretical value: 7
percent error:?
7-5 = 2
(2/7) * 100 = approximately 28.57 %
percent error: 28.57%

Answer 3

(correct answer - incorrect answer) / correct answer

This is the general formula for finding percentage error. You take the difference in the two answers and divide the difference by the correct answer. But you are right, the question doesn't really make sense.

Answer 4

If you have three separate measurements multiplied together, the error of each of the three scales like this:

If Z = A*B*C, and da, db, and dc are the errors on A, B, and C, then:

dz = Z * sqrt[ (da/A)^2 + (db/B)^2 + (dC/C)^2 ]

where dZ is the error on Z (the final answer).

Answer 5

experimental error - theoretical error
---------------------------------------------------
theoretical error


* 100%


that is (E-T)/T * 100

Answer 6

(actual-theoretical)/theoretical