Day 2 of a quick unit on rigid transformations - congruence in terms of rigid motion.
Our big idea for today was to focus on reflect and rotate in the coordinate plane, finding the connection between algebraic rules and what the transformation does in words.
We did grade and check HW #2, which seemed easy for most. Make sure that when you do a coordinate plane transformation from the textbook that you: copy the figure from the graph and label its vertices with appropriate letters, write coordinates next to those vertices if you cannot tell what the transformation is, check to see if this transformation is one of the ones we figured out today, graph the new polygon and label its vertices like A', B', C', etc.
We discovered today in our investigation:
(x,y) to (-x,y) is a reflection across the y-axis
(x,y) to (x,-y) is a reflection across the x-axis
(x,y) to (-x,-y) is a rotation of 180 degrees around the origin
(OR a reflection across one axis and then the other)
(x,y) to (y,x) is a reflection across y=x (positive diagonal through origin.
(x,y) to (-y,-x) is a reflection across y= -x.
We also determined not to learn rules for rotating 90 or 270 degrees. We learned about using perpendicular slopes or patty paper, not algebraic rules.
Rotations can always be checked with patty paper.
HW #3 is pp 115-118: 1-2,4-6, 9, 11-17,20,22,27.
Graph paper and patty paper are available in my room.
Students got to see their test scores.
Notes are not attached, as they are given above in what we discovered in investigation. Be sure to use examples from textbook pp 112-113.
Remember that beginning with #13, you are just writing a rule. You do not need to graph.
Our big idea for today was to focus on reflect and rotate in the coordinate plane, finding the connection between algebraic rules and what the transformation does in words.
We did grade and check HW #2, which seemed easy for most. Make sure that when you do a coordinate plane transformation from the textbook that you: copy the figure from the graph and label its vertices with appropriate letters, write coordinates next to those vertices if you cannot tell what the transformation is, check to see if this transformation is one of the ones we figured out today, graph the new polygon and label its vertices like A', B', C', etc.
We discovered today in our investigation:
(x,y) to (-x,y) is a reflection across the y-axis
(x,y) to (x,-y) is a reflection across the x-axis
(x,y) to (-x,-y) is a rotation of 180 degrees around the origin
(OR a reflection across one axis and then the other)
(x,y) to (y,x) is a reflection across y=x (positive diagonal through origin.
(x,y) to (-y,-x) is a reflection across y= -x.
We also determined not to learn rules for rotating 90 or 270 degrees. We learned about using perpendicular slopes or patty paper, not algebraic rules.
Rotations can always be checked with patty paper.
HW #3 is pp 115-118: 1-2,4-6, 9, 11-17,20,22,27.
Graph paper and patty paper are available in my room.
Students got to see their test scores.
Notes are not attached, as they are given above in what we discovered in investigation. Be sure to use examples from textbook pp 112-113.
Remember that beginning with #13, you are just writing a rule. You do not need to graph.