1. Given a rhombus with diagonals intersecting at the center, one half of the horizontal diagonal is $2.5$ units and one half of the vertical diagonal is $5.5$ units. 2. The length of the diagonals are $d_1 = 2 \times 2.5 = 5$ and $d_2 = 2 \times 5.5 = 11$. 3. The area of a rhombus is given by $$\text{Area} = \frac{d_1 \times d_2}{2} = \frac{5 \times 11}{2} = 27.5.$$ 4. Since the angle given (45°) confirms the shape but does not affect area calculations using diagonals, the area remains $27.5$. Final answer: The area of the rhombus is $27.5$ square units.