Angle addition, angle bisectors, and congruent angles
- Adding lengths, then adding angles — 3 tasks
- Where the middle ray has to be — 3 tasks
- Which angles may be added — 3 tasks
- The ray that cuts an angle in half — 4 tasks
- Going Deeper — 6 tasks
- Practice — 24 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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Angle Addition — Cut & Glue Sort 25 minutes, including the cutting · 5 sheets
12 pieces, each a few rays from one point and one angle asked for, sorted without any arithmetic into add the two, take one from the other, or no equation gives it — where the last row holds angles that share only a vertex, angles that overlap, and an angle beyond both.
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Angle Addition & Angle Bisectors — Answer Maze 10–15 minutes · 4 sheets
One page and nothing to prepare: 8 boxes, each a small figure asking for one angle — a part, a half or the whole — where the wrong answer is the operation turned round or a number that was not asked for, and leads to a box that sends you back.
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Angle Bisectors — Mystery Picture 25–35 minutes · 4 sheets
25 angles, each with one stroke from its vertex — some marked with matching arcs, equal numbers or little squares, some drawn dead center with no marks, some lines running on through the vertex: fill only the ones that are the bisector, and a picture appears.
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Angle Addition & Angle Bisectors — Scavenger Hunt a full class period · 13 sheets
16 cards round the room: a part from the whole, a half from a bisected angle, the whole from a half, a bisector inside a longer chain, and expressions on the parts — each asks for one angle, a wrong answer lands on a card that sends the group back, and a clean run is 8 lines on the record sheet.