Finding the Fourth Proportional to 1,128.83, 1,558.32 and 686.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.83 : 1,558.32 = 686.98 : x
2. Step 2: Convert to fraction form
   1,128.83/1,558.32 = 686.98/x
3. Step 3: Cross multiply
   1,128.83x = 1,558.32 × 686.98
4. Step 4: Simplify right side
   1,128.83x = 1,070,526.88
5. Step 5: Solve for x
   x = 1,070,526.88/1,128.83
6. Step 6: Final answer
   x = 948.35