Reflections in the coordinate plane
- Four equations, one picture — 3 tasks
- The two axis mirrors, and their rules — 3 tasks
- The two slanted mirrors — 6 tasks
- A whole figure, and a check that is not looking — 3 tasks
- A fifth mirror, and two at once — 7 tasks
- Practice — 25 tasks
- Summary — 2 tasks
- Cool-down — 3 tasks
Classroom activities
Things a class does rather than writes on. Each one is a finished PDF: print it, cut it up if it says so, and hand it round.
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Reflections in the Coordinate Plane: Which Mirror — or None? — Cut & Glue Sort 25 minutes, including the cutting · 5 sheets
12 pieces — rules in letters, points and their images, the points a motion leaves where they are, and an L with its image on squared paper — sorted into the reflection in y = x, the reflection in y = −x, and "no reflection does this", where a half-turn, a slide and two different mirrors wait for the student who checks only one thing.
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Reflections: Which Mirror, Which Sign? — Answer Maze 10–15 minutes · 4 sheets
One page and nothing to prepare: 8 boxes that reflect a point in the x-axis, the y-axis, y = x and y = −x, name the mirror from a point and its image, and pick a mirror's rule — where each wrong answer is one of the ways the four rules decay into each other, and leads to a box that sends you back.
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Reflections: Did It Land in the Right Place? — Mystery Picture 25–35 minutes · 4 sheets
25 squares, each a point, a mirror named one of several ways, and where the point is said to land: fill the square if that is the right image. The wrong ones exchange the axis rules, change both signs, confuse y = x with y = −x, or move a point that lies on its mirror — and when every square is right, a picture appears.
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Reflections in the Coordinate Plane — Scavenger Hunt a full class period · 13 sheets
16 cards round the room: reflect a point in the x-axis, the y-axis, y = x or y = −x, each named more than one way; find the original from its image; find the mirror from one point and use it on another — every answer is a point, a wrong answer lands on a card that sends the group back, and a clean run is 8 lines on the record sheet.