Finding the Fourth Proportional to 1,128.59, 1,557.61 and 631.26

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.59 : 1,557.61 = 631.26 : x
2. Step 2: Convert to fraction form
   1,128.59/1,557.61 = 631.26/x
3. Step 3: Cross multiply
   1,128.59x = 1,557.61 × 631.26
4. Step 4: Simplify right side
   1,128.59x = 983,256.89
5. Step 5: Solve for x
   x = 983,256.89/1,128.59
6. Step 6: Final answer
   x = 871.23