Perpendicular lines and their angle relationships
- The two facts at a crossing — 3 tasks
- Perpendicular is about the lines, not the ink — 3 tasks
- One square, four right angles — 3 tasks
- Perpendicular and parallel, both ways — 3 tasks
- Going Deeper — 6 tasks
- Practice — 22 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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Perpendicular Lines — Cut & Glue Sort 25 minutes · 5 sheets
12 figures to cut out and glue into 3 bins — these marks make the lines parallel, these make them perpendicular, these settle nothing — and several are drawn so that the eye picks the wrong bin and only the marks get it right.
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Perpendicular Lines — Answer Maze 10–15 minutes · 4 sheets
One page and nothing to prepare: each box is a pair of right angles, and the question is which theorem the figure hands you — the one that ends at parallel lines or the one that starts from them — with the row of box numbers at the foot to mark it by.
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Perpendicular Lines — Mystery Picture 25–35 minutes · 4 sheets
25 figures and no numbers: fill the square with slanted lines where the marks force the two marked angles to add to 90°, leave it white where they do not — and neither “there is a corner” nor “there is a little square” gets the sheet right.
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Perpendicular Lines — Scavenger Hunt a full class period · 13 sheets
16 cards round the room: one small square makes all four angles right angles, and each card asks whether the two marked angles are complementary or supplementary before it gives you the number that finds the next card; a wrong answer lands on a card that names the mistake and sends you back, so a clean run is 8 lines on the record sheet.