Finding the Fourth Proportional to 1,128.94, 1,557.81 and 631.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.94 : 1,557.81 = 631.57 : x
2. Step 2: Convert to fraction form
   1,128.94/1,557.81 = 631.57/x
3. Step 3: Cross multiply
   1,128.94x = 1,557.81 × 631.57
4. Step 4: Simplify right side
   1,128.94x = 983,866.06
5. Step 5: Solve for x
   x = 983,866.06/1,128.94
6. Step 6: Final answer
   x = 871.50