Final answer:
The area of a rhombus is calculated by multiplying its base by its height. Since the side of the rhombus is 5 cm and the height is 3 cm, the area is 15 cm², which corresponds to answer B.
Step-by-step explanation:
The area of a rhombus can be found using the formula: Area = base × height. Given that the side of the rhombus is 5 cm, which is also the base, and the height is 3 cm, we can plug these values into our formula to get the area. The calculation would be: Area = 5 cm × 3 cm = 15 cm²
Therefore, the correct answer is B. 15cm².