A steel beam rests on supports 2.5 m apart…

Step 1. On edge. $\delta = \dfrac{3.0 \times 10^{3}\ \text{N} \times (2.5\ \text{m})^3}{4 \times 0.060\ \text{m} \times (0.12\ \text{m})^3} \times \dfrac{1}{2.0 \times 10^{11}\ \text{Pa}} = 5.65 \times 10^{-4}\ \text{m}$.

Step 2. Laid flat. $bd^3$ becomes $0.12\ \text{m} \times (0.060\ \text{m})^3$, four times smaller, so $\delta = 2.26\ \text{mm}$.