Finding the Fourth Proportional to 1,031.76, 1,423.24 and 638.52

Step by Step Solution

1. Step 1: Write the proportion equation
   1,031.76 : 1,423.24 = 638.52 : x
2. Step 2: Convert to fraction form
   1,031.76/1,423.24 = 638.52/x
3. Step 3: Cross multiply
   1,031.76x = 1,423.24 × 638.52
4. Step 4: Simplify right side
   1,031.76x = 908,767.20
5. Step 5: Solve for x
   x = 908,767.20/1,031.76
6. Step 6: Final answer
   x = 880.79