Elections: Sampling variability and standard error

Polls showed the two main candidates in the 2004 presidential election were nearly tied on the day before the election. To predict the winner, a newspaper would like to have a poll that has margin of error less than 1%. Roughly how large a sample would be needed for such a poll?

I attached an image to show a graphical representation of the sample size needed to get the margin or errors.
To get a margin of error of 5% we would need 384
To get a margin of …

This solution helps solve to find the required sample size needed for a certain margin of error.