It will help to graph it, so that you can see the shape. However, you can also just solve it by looking at the vertices. If you graph it, you'll see that the shape is a trapezoid. The two bases are 4 and 6, while the height is 5 - 1 = 4. So, we solve by using the equation for the area of a trapezoid: (6 + 4) * 4 * .5 = 20 units squared.