Mathematics Geometry Conceptual 11–13 yrs

Properties of triangles and quadrilaterals

三角形与四边形的性质

Description

Derive and illustrate properties of triangles, quadrilaterals, and circles using appropriate language, including interior angles, diagonals, symmetry, and relationships between side lengths

Mastery Evidence

✓ List and verify properties of a parallelogram (opposite sides parallel/equal, opposite angles equal, diagonals bisect each other)
✓ Explain why a square is a special case of both a rectangle and a rhombus
✓ Derive the relationship between the radius, diameter, and circumference of a circle

Assessment Prompt

If you ask your child why the diagonals of a rectangle are always equal in length, can they explain it using the properties of the shape — rather than just measuring to check?