standard_description: Explain how the criteria for triangle congruence (ASA, SAS, and SSS) follow from the definition of congruence in terms of rigid motions.
problem_activity: Narrative
The purpose of this activity is for students to draw shapes. Students draw straight lines to connect the dots to create shapes. Some students may benefit from a ruler or straight edge to assist them. Students draw some shapes that they can name, such as triangles and rectangles. They also draw some shapes that they have not been introduced to the formal names of. Students can describe the attributes of these shapes but are not expected to name the shapes.
Launch
Display the first image of four big red dots from the student book.
“What do you notice? What do you wonder?” (There are black dots. There are 4 big red dots.)
30 seconds: quiet think time
30 seconds: partner discussion
Share responses.
“These dots will help us draw shapes. I need to connect the red dots using straight lines.”
Demonstrate drawing a straight line between 2 of the red dots.
“Where should I draw the next line?”
Repeat until the rectangle is drawn.
“What shape did I draw?” (A rectangle.)
Activity
“Draw straight lines to connect the dots. When you’re finished, color in the shape and tell your partner about the shape you drew.”
6 minutes: partner work time
Student Facing
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Synthesis:
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Student Response
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Activity Synthesis
Display the last image with 3 red dots.
“Tyler is connecting the dots. What shape do you think he is going to make? Why?” (A triangle. There are 3 dots so there will be 3 sides. Triangles have 3 sides.)
If needed, ask “How many corners will the shape have? How many sides will the shape have?”


aligns: no