Finding the Fourth Proportional to 1,139.50, 1,572.34 and 667.44

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.50 : 1,572.34 = 667.44 : x
2. Step 2: Convert to fraction form
   1,139.50/1,572.34 = 667.44/x
3. Step 3: Cross multiply
   1,139.50x = 1,572.34 × 667.44
4. Step 4: Simplify right side
   1,139.50x = 1,049,442.61
5. Step 5: Solve for x
   x = 1,049,442.61/1,139.50
6. Step 6: Final answer
   x = 920.97