Look at the coordinate plane. First start with the bottom side (LN). The line goes from -3 to 9. This means that the line is 12 units long. Now, look at the other sides. MN goes from 3 to 9, therefore, the line is 6 units long. Lastly, look at ML— -3 to 3, therefore, the line is 6 units long. Add them all up, (12+6+6) and it equals 24 units.
