An airplane takes off 12 and a half miles south of the city and flies due north at a constant speed of 180 miles per hour what is the plane's position relative to the city after 45 minutes

So we know that 45 is 1/4 of 60 minutes so the plane flew 3/4 hour

it started 12 and 1/2 miles south and the airplane flew opposite that so the distance is 3/4 times 180-12.5 or 135-12.5=122.5 miles away from the city north