City A is due north of city B Find the distance between the cities and assume that the radius of the earth is 3960 miles. So the first thing we need to do is we need to realize when we're talking about the distance, we're really talking about S equal R Theta talking about the distance on the earth or an arc. So when we have S equal R Theta, we need the thetas to be in terms of radiance. So we have 45° seven minutes. So the first thing to do is to change that into degrees. So 45° + 7 / 60. Now that's a new measure because remember 7 minutes is really the same thing as 60 minutes in 1° or seven 60th degree. So then we're going to take the 20° 55 minutes and do the same thing, so 20 + 55 / 60, and that makes it convert to degrees. But then we need to change those degrees into radians. So we're going to multiply by π radians over 180°, and we're going to multiply the other one by π radians over 180°. Now Π radians and 180° are really the equivalent of 1. So once we do that, we're going to then subtract. We're going to take this 45° seven minutes and we're going to subtract 20 degrees, 55 minutes. And if we do all of this, we get 121 Pi over 900 radiance. Should check my math, but I'm pretty sure that's right. So now it's just a matter of S equal R, which was 121 Pi over 900. Actually that was our Theta, S equal R Theta. I'm doing these in the wrong order. That's my R and here's my Theta. So I get S being approximately 1673 because it asked to round to the nearest mile. So 121 Pi over 900 times 396-0016 seven 3 miles.