The area of a rhombus can be calculated using the formula:
\[ \text{Area} = \text{base} \times \text{height} \]
In this case, we know that each side of the rhombus is 5 cm, but what we need to focus on here is the height, which is given as 3 cm.
So, we can use the side length (which acts as the base in this context) and the height:
\[ \text{Area} = 5 , \text{cm} \times 3 , \text{cm} = 15 , \text{cm}^2 \]
Thus, the area of the rhombus is \( \mathbf{15 , cm^2} \).