Which formula is correct for calculating the area of a rhombus?

The area of a rhombus can be accurately calculated using the formula that involves the lengths of its diagonals. Specifically, the correct formula is one-half multiplied by the length of the first diagonal and the length of the second diagonal. This means that by measuring both diagonals of the rhombus and applying this formula, you can effectively find the area enclosed by the four equal-length sides.

This method is particularly useful because the diagonals of a rhombus intersect at right angles, ensuring that their product gives a measurement that can directly translate to the area. This allows for a straightforward calculation without needing to find the height or base that may require additional steps or measurements.

In contrast, the other provided formulas either pertain to different geometrical shapes or do not apply as effectively to calculate the area of a rhombus specifically. Understanding the properties of the diagonals not only simplifies the area calculation but also highlights the unique characteristics of the rhombus compared to other quadrilaterals.