Finding the Fourth Proportional to 1,128.94, 1,557.91 and 631.62

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.94 : 1,557.91 = 631.62 : x
2. Step 2: Convert to fraction form
   1,128.94/1,557.91 = 631.62/x
3. Step 3: Cross multiply
   1,128.94x = 1,557.91 × 631.62
4. Step 4: Simplify right side
   1,128.94x = 984,007.11
5. Step 5: Solve for x
   x = 984,007.11/1,128.94
6. Step 6: Final answer
   x = 871.62