Angle Chase Game
Calculate missing angles in straight lines and triangles using geometric relationships.
Choose Practice or Daily to begin.
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Instructions, device progress and accessibility
Choose Easy, Normal or Hard and select Practice or a daily puzzle based on the UTC date. Enter answers, then select Check answer. Hints and Undo mark a round as assisted. Best scores and progress are stored only in this browser; no account is needed.
Local progress is checked when play begins.
How to play Angle Chase
Study the angles in the displayed figure description, then calculate the missing angles. Use 180° for straight lines and triangles; triangle exterior angles equal the sum of the two remote interior angles.
Worked example
In a triangle with angles 55° and 65°, the third angle is 60°. Its adjacent exterior angle is 120°.
Math formulas and key skills
Straight line: A + B = 180°. Triangle: A + B + C = 180°. Adjacent exterior angle = 180° − interior angle.
Avoid common mistakes
Do not confuse an interior angle with its adjacent exterior angle. Always label the angle asked for.
Frequently asked questions
What do the angles in a triangle add up to?
The three interior angles of a Euclidean triangle add up to 180°.
How do I find an exterior angle?
An exterior angle adjacent to an interior angle equals 180° minus that interior angle.