1. **State the problem:** We have two similar triangles ABC and DEF. We know sides CB = 17 and CA = 10.1 in triangle ABC, and side FE = 54 in triangle DEF. We need to find side FD in triangle DEF. 2. **Recall the property of similar triangles:** Corresponding sides of similar triangles are proportional. This means: $$\frac{CB}{FE} = \frac{CA}{FD}$$ 3. **Set up the proportion:** Using the corresponding sides, $$\frac{17}{54} = \frac{10.1}{FD}$$ 4. **Solve for FD:** Cross-multiply to get $$17 \times FD = 54 \times 10.1$$ 5. **Calculate the right side:** $$54 \times 10.1 = 545.4$$ 6. **Isolate FD:** $$FD = \frac{545.4}{17}$$ 7. **Simplify the fraction:** $$FD = \frac{\cancel{545.4}}{\cancel{17}} = 32.1$$ 8. **Final answer:** The length of side FD is approximately **32.1** units.