When construction workers build a house, they start with a process called framing. Using long, narrow pieces of lumber, the workers build a "frame" that will support the rest of the house and give it a solid structure. Look at the image below of a framed house. What kinds of lines do you see? How do the lines relate to each other?

Some lines appear vertical, some appear horizontal, while other lines cross each other. In other words, the frame includes parallel, perpendicular, and intersecting lines. Most of the intersecting lines are perpendicular.

How would you describe the lines in these photographs? When you think you know how to describe them, click each image to check your answer.