Finding the Fourth Proportional to 1,129.41, 1,558.17 and 687.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,129.41 : 1,558.17 = 687.15 : x
2. Step 2: Convert to fraction form
   1,129.41/1,558.17 = 687.15/x
3. Step 3: Cross multiply
   1,129.41x = 1,558.17 × 687.15
4. Step 4: Simplify right side
   1,129.41x = 1,070,696.52
5. Step 5: Solve for x
   x = 1,070,696.52/1,129.41
6. Step 6: Final answer
   x = 948.01