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Triangle Sum Theorem Worksheets and Activities

The three angles of a triangle add to 180°: missing angles, right, isosceles and equilateral triangles, angles written with x, the Exterior Angle Theorem and word problems.

This unit is written for 8th Grade and Geometry. Buy the whole unit bundle for $20.00, or just the piece you need: cut & paste, error analysis, escape room, guided notes, matching, maze and test prep. Every page comes as a print-ready PDF plus an editable Word file, with a full answer key.

The complete unit

Unit Bundle

Triangle Sum Theorem

Everything below in one download: cut & paste, error analysis, escape room, guided notes, matching, maze, test prep.

$20.00View on TPT →

Each Triangle Sum Theorem activity on its own

Cut & Paste

Triangle Sum Theorem: Cut & Paste

Students cut, sort and glue. Wrong placements are visible from across the room.

$3.00View on TPT →

Error Analysis

Triangle Sum Theorem: Error Analysis

Worked problems with one real student mistake. Students find it, explain it and fix it.

$3.00View on TPT →

Escape Room

Triangle Sum Theorem: Escape Room

Three paper levels and a decoder. No locks or props to buy, and a wrong answer will not decode.

$3.00View on TPT →

Guided Notes

Triangle Sum Theorem: Guided Notes

Worked examples one step per line, with PowerPoint and SMART Notebook slides, blank and completed.

$6.00View on TPT →

Matching

Triangle Sum Theorem: Matching

Cards that only pair one way, so a wrong match shows itself. Good for partners and stations.

$3.00View on TPT →

Maze

Triangle Sum Theorem: Maze

Self-checking: students follow their answer to the next square, and a wrong answer leads nowhere.

$3.00View on TPT →

Test Prep

Triangle Sum Theorem: Test Prep

Mixed multiple choice and written questions in state-test wording, answer key with the work shown.

$3.00View on TPT →

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