You should look up in a table how big the chance is that a N(0, 1) distributed number is < 0.8, then take 1 - that to get the risk of falling outside. Then you should do the same thing the check the chanse that a N(0, 1) number is > -0.5. You then add the chances of falling outside. You now get the total risk of falling outside, on any of the sides. Take 1 - that to get the probability that a pole is between 74.5 and 75.8.
Note: Your table may not cover negative numbers (this is most likely). Then realize that the chance of the number being > -0.5 is the same as the chance of the number being < 0.5, because of the symmetry around 0.