Find the area of a rhombus if its diagonals are 2.5dm and 4cm.

Given:
rhombus ABCE,
AC and BE – diagonals,
AC = 2.5 decimeters,
BE = 4 centimeters.
Find the area of the rhombus ABCE, that is, S ABCE -?

Decision:
1. Consider a rhombus ABCE. Let’s convert the length of the AC diagonal from decimetres to centimeters and get:
AC = 2.5 decimetres = 25 centimeters.
2. The area of a rhombus is equal to the product of its diagonals and an ordinary fraction 1/2. Hence:
S ABCE = 1/2 * AC * BE;
S ABCE = 1/2 * 4 * 25;
S ABCE = 2 * 25;
S ABCE = 50 cm ^ 2.
Answer: 50 cm ^ 2.