Mathematics Geometry Conceptual 12–14 yrs

Angles in triangles (age 12+)

三角形中的角（12岁以上）

Description

Know and use the criteria for triangle congruence (SSS, SAS, ASA, RHS), use standard labelling conventions for sides and angles of triangle ABC, and determine whether two triangles are congruent

Mastery Evidence

✓ State which congruence criterion (SSS, SAS, ASA, or RHS) applies to a given pair of triangles
✓ Use the notation △ABC ≅ △DEF and match corresponding sides and angles
✓ Determine whether given measurements produce a unique triangle, more than one, or none

Assessment Prompt

If your child is shown two triangles where all three sides of one match all three sides of the other, can they explain why those triangles must be identical in shape and size?