Finding the Fourth Proportional to 1,128.88, 1,557.90 and 656.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.88 : 1,557.90 = 656.80 : x
2. Step 2: Convert to fraction form
   1,128.88/1,557.90 = 656.80/x
3. Step 3: Cross multiply
   1,128.88x = 1,557.90 × 656.80
4. Step 4: Simplify right side
   1,128.88x = 1,023,228.72
5. Step 5: Solve for x
   x = 1,023,228.72/1,128.88
6. Step 6: Final answer
   x = 906.41