Finding the Fourth Proportional to 1,128.30, 1,557.06 and 630.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.30 : 1,557.06 = 630.96 : x
2. Step 2: Convert to fraction form
   1,128.30/1,557.06 = 630.96/x
3. Step 3: Cross multiply
   1,128.30x = 1,557.06 × 630.96
4. Step 4: Simplify right side
   1,128.30x = 982,431.64
5. Step 5: Solve for x
   x = 982,431.64/1,128.30
6. Step 6: Final answer
   x = 870.72