If your printout is a different size than mine, then the distance you measure between points A and B will be different from the distance I get. As a result, the gradient you get will be different than the answer shown above.
To check if your gradient is correct, multiply your gradient by your horizontal distance (in feet) divided by my horizontal distance (in feet). If the result you get is equal to my gradient, then your answer is correct.

© 2010 David Leveson/Revised by G. Rocha and Michelle O'Dea