Geometry - Lozenge

Lozenge (Rhombus)

Understanding the Lozenge in Geometry: Definition, Properties, and Key Formulas

A lozenge, commonly known as a rhombus, is a special type of parallelogram where all four sides are of equal length. Unlike a square, the angles are not necessarily right angles. Lozenge shapes are symmetrical and often appear in tiling, design patterns, and geometry.

Diagram of a lozenge (rhombus) showing diagonals, height, and angles.

Key Properties of a Lozenge

  1. All Sides Equal: Every side has the same length.
  2. Opposite Angles: Equal in measure.
  3. Diagonals: Bisect each other at right angles.
  4. Angles: Adjacent angles are supplementary (\(180^\circ\)).
  5. Special Case: A square is a lozenge with all angles equal to \(90^\circ\).

Key Formulas for a Lozenge

1. Perimeter \(P\):

The total length around the lozenge:

\[ P = 4a \]

where:

  • \(a\): Length of one side

2. Area \(A\):

The area can be calculated using either the diagonals or base and height:

\[ A = \frac{m \times n}{2} = a \times h \]

where:

  • \(m, n\): Lengths of diagonals
  • \(a\): Side length
  • \(h\): Height (perpendicular distance between opposite sides)

3. Angle Relationship:

The sum of adjacent angles is always \(180^\circ\):

\[ \alpha + \beta = 180^\circ \]

4. Diagonal Formula:

Relationship between side length and diagonals:

\[ m^2 + n^2 = 4a^2 \]

Derived using the Pythagorean theorem, as diagonals intersect at right angles.

5. Height \(h\):

Height can be computed using two different formulas:

\[ h = \frac{mn}{2a} = a \sin(\alpha) \]

where:

  • \(mn\): Product of diagonals
  • \(\alpha\): Interior angle

Applications of the Lozenge

  • Art & Design: Common in tile patterns, embroidery, and heraldry.
  • Geometry: Used in understanding symmetry, congruence, and area calculation.
  • Construction: Found in structural bracing and decorative frameworks.
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