A banker wants to estimate the true mean of how much money adults keep in their bank accounts. He wants to be 95% confident that he is within $100.How many people does he need to sample if the standard deviation is $252.73?

Don't know sorry

Step-by-step explanation:

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.