Finding the Fourth Proportional to 2,815.72, 4,218.10 and 1,355.89

Step by Step Solution

1. Step 1: Write the proportion equation
   2,815.72 : 4,218.10 = 1,355.89 : x
2. Step 2: Convert to fraction form
   2,815.72/4,218.10 = 1,355.89/x
3. Step 3: Cross multiply
   2,815.72x = 4,218.10 × 1,355.89
4. Step 4: Simplify right side
   2,815.72x = 5,719,279.61
5. Step 5: Solve for x
   x = 5,719,279.61/2,815.72
6. Step 6: Final answer
   x = 2,031.20