Lesson Standard: 8.G.1
Content Objective: Students will come to understand that translations (reflections, rotations) changes the position but will not compromise the size and shape (integrity) of a geometric figure. Recognize congruence with a one-to-one correspondence (mapping).
Mathematical practice(s): 1, 4, 6
Lesson Design / What will the teacher be doing? / What will the students be doing?(Structured Student Interaction) / What will the teacher be listening for?
(What do we expect students to say?) / Probing Questions for Differentiation
Assessing Questions
(“stuck”) / Advancing Questions
(further learning)
Engage (Launch)
Pose function using points ( x +5, y)
Example:
(1, 2) (6, 2)
(3, 5) (8, 5)
(4, 1) ( , ) / Ask students for three points (first quadrant) for preimage. Record on board.
Give two points of image. Pose question for next point.
Poll class first:
How many people think it will be bigger/smaller/or the same? Or not sure
Teacher graph on the preimage on doc cam.
Have students graph the preimage and image / Partner A tell B what the next point is. How did you get it? Partner B, agree/disagree…why
Sentence Frame (below lesson plan) / Figure got bigger
Figure moved to right / What shape do you think we created?
What happened to the figure? / Use extra letters first…
Highlight A to A’ (first move) Too many letters (confusing), so new way to label
Activity or Task 1
Pose function using points (x, y - 3) / Use same 3 points
Give two points of image. Pose question for next point.
Poll the class
If we graph this, will this result in a triangle?
What do you expect is going to happen to the figure? / Partner B tell A what the next point is. How did you get it? Partner B, agree/disagree…why
Sentence Frame / Figure moved to left
Figure moved down / Can you write an algebraic rule?
Activity or Task 2
Pose function using points (x – 1, y + 4) / Use same 3 points
Give two points of image. Pose question for next point.
What do you expect is going to happen to the figure?
Have students graph the preimage and image / Partner B tell A what the next point is. How did you get it? Partner B, agree/disagree…why
Sentence Frame
Activity or Task 3
Start with preimage in quadrant I and place A’ in quadrant III / Pose:
Show preimage and A’
What steps can you come up with to translate the preimage to the image? / Work independently first
Partners work together
Partner A poses possible first step, Partner B then the poses next step / Can you write an algebraic rule?
Closure
Speaker 1: I think the figure will be ______because ______
Speaker 2: I heard you say ______and….
I agree because ______
I have a different idea because ______