Finding the Fourth Proportional to 1,345.80, 1,856.89 and 1,031.39

Step by Step Solution

1. Step 1: Write the proportion equation
   1,345.80 : 1,856.89 = 1,031.39 : x
2. Step 2: Convert to fraction form
   1,345.80/1,856.89 = 1,031.39/x
3. Step 3: Cross multiply
   1,345.80x = 1,856.89 × 1,031.39
4. Step 4: Simplify right side
   1,345.80x = 1,915,177.78
5. Step 5: Solve for x
   x = 1,915,177.78/1,345.80
6. Step 6: Final answer
   x = 1,423.08