Calculate the area of a rhombus if one of its diagonal is 9 cm, and the second is 10.

Given:

length – 9 cm;

width – 10 cm;

S =? cm².

A rhombus is a rectangle. A rectangle is a quadrangle, not a three-dimensional geometric figure, in which opposite sides are pairwise parallel and equal. The area of a rectangle is equal to the product of its sides and is calculated by the formula: S = a * b.

1) S = 9 * 10 = 90 (cm²).

Answer: 90 cm² area of a rhombus.