Lines and Angles

• Intersecting Angles and Streets

  Students explore the properties of angles, search city maps for intersecting streets, and then design their own street intersection.

  Show 4 Steps

  1. Explore how a lone angle creates a second angle. And the two angles always add up to 360º.

  2. Explore how 2, 4, 6, or even 8 intersecting angles still add up to 360º.

  3. Browse online city maps (Google Maps, Open Street Maps, etc) to find an interesting intersection of streets. Measure these angles and check that they also add up to 360º.

  4. Create their own intersection of streets. They’ll label the street names, mark interesting sights, and measure each angle, ensuring that they add up to 360º.

• The Angles of a Triangle

  Students will inductively discover the rules of a triangle’s angles.

  Show 5 Steps

  1. Students try to create the biggest possible angle inside of a triangle.

  2. They look for triangles with one or more right angles.

  3. Then they add up three angles, trying to find the largest and smallest sums possible.

  4. Students try to create triangles with two and three congruent angles.

  5. We close by posing the question: how are angles and sides related? (Larger/smaller angles mean longer/shorter sides. Same sized angles? Same size sides. )

• Lines, Line Segments, Rays, and Infinity!

  Students debate which is longer: a ray or a line.

  Show 3 Steps

  1. I introduce students to lines, line segments, and rays. Finally, I pose the delicious question: “Which is the longest?”

  2. Now we ponder: “Which has more points on it?”

  3. Finally, students explore an idea such as: “What would a ray think about a line?” or “If a line wrote a poem to a line segment, what would it be like?” They can then create a mini-story, a comic, a play, or whatever you see fit!