When two lines cross each other, they are said to be intersecting. The point at which they cross is called the point of intersection. Intersecting lines form four angles at the point of intersection. These angles are equal in pairs, so they are called vertical angles. When two lines intersect, they also form pairs of corresponding angles, alternate interior angles, and alternate exterior angles. Understanding these angle relationships is important when working with intersecting lines.
Specify locations and describe spatial relationships using coordinate geometry and other representational systems.
Make and use coordinate systems to specify locations and to describe paths.
Connections to the Grade 5 Focal Points (NCTM)
Data Analysis: Students apply their understanding of whole numbers, fractions, and decimals as they construct and analyze double-bar and line graphs and use ordered pairs on coordinate grids.