Finding the Fourth Proportional to 1,128.31, 1,557.09 and 630.94

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.31 : 1,557.09 = 630.94 : x
2. Step 2: Convert to fraction form
   1,128.31/1,557.09 = 630.94/x
3. Step 3: Cross multiply
   1,128.31x = 1,557.09 × 630.94
4. Step 4: Simplify right side
   1,128.31x = 982,429.39
5. Step 5: Solve for x
   x = 982,429.39/1,128.31
6. Step 6: Final answer
   x = 870.71