standard_description: Use informal arguments to establish facts about the angle sum and exterior angle of triangles, about the angles created when parallel lines are cut by a transversal, and the angle-angle criterion for similarity of triangles. For example, arrange three copies of the same triangle so that the sum of the three angles appears to form a line, and give an argument in terms of transversals why this is so.
problem_activity: Activity
In this activity, students practice making connections between different representations of the same situation. If desired, they can also identify and create any missing representations (this would require removing some cards from the sets you distribute). The practice will be helpful when students make connections between verbal and tabular representations in the associated Algebra 1 lesson. A matching task gives students opportunities to analyze representations, statements, and structures closely and make connections (MP7).
Launch
Arrange students in groups of 2. Distribute 1 set of slips from the blackline master to each group. (A complete set if students will only do the matching. A set that is missing a few cards if you would like for students to create some representations.)
Student Facing
Your teacher will give you a set of cards. Each card has either a verbal description, a table, or a graph. Find the three cards that represent the same situation. If one of the three representations for a situation is missing, use the blank cards to create that representation.
Student Response
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Activity Synthesis
Select groups to share their matches and how they determined which verbal descriptions, tables, and graphs were a match. Look for groups that created different representations for the missing ones. Attend to the language that students use to describe their matching representations, giving them opportunities to describe them more precisely.


aligns: no