On a coordinate plane, triangle L M N has points (negative 1, 2), (negative 1, negative 4), and (3, negative 4). What is the area of triangle LMN?

Answer:
The base length (which is the length on MN) is 4 and the height (which is LM) is 6 so the area is 4 * 6 / 2 = 12 sq. units.