Finding the Fourth Proportional to 1,128.50, 1,557.32 and 656.40

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.50 : 1,557.32 = 656.40 : x
2. Step 2: Convert to fraction form
   1,128.50/1,557.32 = 656.40/x
3. Step 3: Cross multiply
   1,128.50x = 1,557.32 × 656.40
4. Step 4: Simplify right side
   1,128.50x = 1,022,221.57
5. Step 5: Solve for x
   x = 1,022,221.57/1,128.50
6. Step 6: Final answer
   x = 905.83