Rhombus area = ½ · d₁ · d₂

Dependencies: Rhombus: diagonals ⊥-bisect, Triangle area = ½ × base × height.

Statement

Let $ABCD$ be a rhombus with diagonals $AC$ and $BD$, of lengths $d_1=|AC|$ and $d_2=|BD|$ respectively. They meet at a point $O$. Then the area of the rhombus is

Unlike a parallelogram or rectangle, whose area is usually expressed as base × height, the rhombus formula is written directly in terms of the two diagonals — so once the diagonals are measured, the area follows immediately.