Area of a Rhombus Model

Eight right triangles show that a rhombus is half of the rectangle formed by its diagonals: Area = ½ × d₁ × d₂.

How it works

1. Fill the rhombus pocket with four of the triangles
2. Fill the rectangle pocket, d₁ by d₂, with all eight triangles
3. The rhombus uses half the triangles, so it is half the rectangle

What students learn

• Area of a rhombus = ½ × d₁ × d₂
• The diagonals of a rhombus cross at right angles
• The diagonals split a rhombus into four equal right triangles

Try these activities

1. Check with d₁ = 12 cm and d₂ = 8 cm: the area is 48 cm²
2. Measure the angle where the diagonals cross
3. Use the same idea to find the area of a kite

Curriculum fit

In the box

• MDF tray 29 x 12 cm (d₁ = 12 cm, d₂ = 8 cm)
• 4 red and 4 blue acrylic triangles
• Step-by-step manual

Pairs well with

Area of a Trapezium ModelMATH-128Area of a Parallelogram ModelMATH-126