2. Session 1 – Triangles Learning Objectives In this session, Mathematicians will: O Use geometric thinking to solve visualization problems. O Use mathematical language to express ideas and to understand the ideas of others. O Construct the basic objects of geometry. O Classify triangles according to some of their features

3. Task 1: QUICK IMAGES You will need a piece of paper and pencil/pen. You'll see an image briefly and then try to draw it from memory on a piece of paper. You will have 3 seconds to view. Part 1: What is Geometry?

4. Task2: BUILDING FROM DIRECTIONS O It looks like a flower. O The symmetric flower has a hexagon as the main flower with a square center. O Outer petals on each side of the main flower are triangles. O The stem and leaves are made from triangles. Part 1: What is Geometry?

5. Task2: BUILDING FROM DIRECTIONS Create your own shape. Your partner will have to re- create it based on your verbal description of your shape Part 1: What is Geometry?

6. Cooperative Learning Groups & Responsibilities Task ATask B Group LeaderTask ManagerMaterials ManagerRecorder Liaison between group and teacher Group speaker Ensure all members are participating, on task, and keeps track of time. Collects and returns all materials for group Records all information necessary on chart paper to reflect participants thoughts and ideas

7. Task B: Different Triangles 1. Draw any triangle on your paper 2. Draw a second triangle that is different in some way from your first one. Describe in just word or two how it is different. 3. Draw a third triangle that is different from both of your other two. Describe how it is different. 4. Draw two more triangles, different from all of the ones that came before it. 5. To make “different” triangles you have to change some features of the triangle. Make a list of features of triangles that you changed. Part 2: Triangles and Quadrilaterals

8. Task A: Triangle Sort 1. Sort the entire collection into three groups so that no triangle belongs to two groups. 2. Give a description or name to each of the groups and record on chart paper. 3. Once you have found one criterion for sorting. Determine a second. Part 2: Triangles and Quadrilaterals

9. Task 1: Classifying Triangles The following shows how triangles can be classified according to some of their features: ANGLES, SIDES, SIZE Part 2: Triangles and Quadrilaterals

10. O Sketch a triangle in each of the nine cells. O Of the nine cells in the chart, two of them are impossible to fill. Can you tell which ones and why? Part 2: Triangles and Quadrilaterals