plz help me mathematics problem

Question

A small radio transmitter broadcasts in a 43 mile radius. If you drive along a straight line from a city 55 miles north of the transmitter to a second city 51 miles east of the transmitter, during how much of the drive will you pick up a signal from the transmitter?

Answer 1

First draw a picture and place the transmitter at the origin of a coordinate system (the x and y axes). Draw a point for the city to the north and another point for the city to the east. Draw a line between the points. Find the equation for the line. When values on that line are less than 43, you can hear a transmission from the transmitter.