Mathematics
Geometry
Procedural
10–11 yrs
Angles in triangles (age 10+)
三角形中的角（10岁以上）
Description
Find unknown angles in triangles, quadrilaterals, and regular polygons using angle sum properties
Mastery Evidence
- Find a missing angle in a triangle given two angles (using angle sum = 180°)
- Calculate a missing angle in a quadrilateral (angle sum = 360°)
- Calculate the interior angle of a regular hexagon from the angle sum formula
Assessment Prompt
If your child knows that angles in a triangle always add up to 180°, and two angles in a triangle are 55° and 70°, can they work out the third angle without measuring it?
