Finding the Fourth Proportional to 1,139.54, 1,572.68 and 667.41

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.54 : 1,572.68 = 667.41 : x
2. Step 2: Convert to fraction form
   1,139.54/1,572.68 = 667.41/x
3. Step 3: Cross multiply
   1,139.54x = 1,572.68 × 667.41
4. Step 4: Simplify right side
   1,139.54x = 1,049,622.78
5. Step 5: Solve for x
   x = 1,049,622.78/1,139.54
6. Step 6: Final answer
   x = 921.09