1. **State the problem:** Multiply 57.50 by 5. 2. **Formula used:** Multiplication of two numbers is given by $$a \times b$$ where $a=57.50$ and $b=5$. 3. **Calculate:** $$57.50 \times 5 = 287.50$$ 4. **Explanation:** Multiplying 57.50 by 5 means adding 57.50 five times or scaling 57.50 by a factor of 5. 5. **Final answer:** $$287.50$$