Finding the Fourth Proportional to 1,031.57, 1,423.83 and 638.37

Step by Step Solution

1. Step 1: Write the proportion equation
   1,031.57 : 1,423.83 = 638.37 : x
2. Step 2: Convert to fraction form
   1,031.57/1,423.83 = 638.37/x
3. Step 3: Cross multiply
   1,031.57x = 1,423.83 × 638.37
4. Step 4: Simplify right side
   1,031.57x = 908,932.75
5. Step 5: Solve for x
   x = 908,932.75/1,031.57
6. Step 6: Final answer
   x = 881.12