Unit 8 · Polygons and Quadrilaterals

8.5Rhombi and Squares

Quick Answer

A rhombus is a parallelogram with four congruent sides; its diagonals are perpendicular bisectors of each other and bisect the vertex angles. A square is both a rectangle and a rhombus.

Essential Question

How do the diagonal properties of a rhombus differ from those of a rectangle, and what makes a square the most special parallelogram?

Learning Goals

  • 1Define rhombus and state its diagonal properties.
  • 2Apply the rhombus diagonal theorems.
  • 3Define a square as a rectangle and a rhombus.
  • 4Classify quadrilaterals using a hierarchy.

Key Vocabulary

Rhombus

A parallelogram with four congruent sides.

Rhombus Diagonal Theorem

The diagonals of a rhombus are perpendicular bisectors of each other and bisect the vertex angles.

Square

A quadrilateral that is both a rectangle and a rhombus.

Full lesson content coming soon

Worked examples, guided practice problems, a workbook, quiz, and downloadable PDF resources will be added to this lesson in Phase 2. The learning goals and vocabulary above reflect the complete lesson scope.