Rhombus diagonals are perpendicular bisectors

All sides equal; diagonals bisect each other at right angles and bisect the vertex angles.

Key formulas

d₁² + d₂² = 4a²
area = (d₁d₂)/2

Properties pack

A rhombus is a parallelogram with equal sides. Diagonals are perpendicular and bisect each other.

Area shortcut

Area = half product of diagonals. Diagonals 6 and 8 → area 24.

Side from diagonals

Half-diagonals 3 and 4 → side 5 by Pythagoras.

Worked example

Worked example

Problem. A rhombus has diagonals 6 cm and 8 cm. Find its side length and area.

Solution. Half-diagonals 3 and 4 form a right triangle: side = 5 cm. Area = (d₁d₂)/2 = 24 cm².

Square special case

A square is a rhombus with equal diagonals.

Review quiz

Diagonals 10 and 24. Rhombus side is:

Practice questions

  1. Diagonals 10 and 24. Find the side and the area.
  2. Why do the diagonals bisect the angles of a rhombus?

Study notes

Are diagonals equal?

Only if the rhombus is a square.

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