Finding the Fourth Proportional to 1,128.89, 1,558.20 and 656.90

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.89 : 1,558.20 = 656.90 : x
2. Step 2: Convert to fraction form
   1,128.89/1,558.20 = 656.90/x
3. Step 3: Cross multiply
   1,128.89x = 1,558.20 × 656.90
4. Step 4: Simplify right side
   1,128.89x = 1,023,581.58
5. Step 5: Solve for x
   x = 1,023,581.58/1,128.89
6. Step 6: Final answer
   x = 906.72