Finding the Fourth Proportional to 1,008.54, 1,391.58 and 615.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,008.54 : 1,391.58 = 615.69 : x
2. Step 2: Convert to fraction form
   1,008.54/1,391.58 = 615.69/x
3. Step 3: Cross multiply
   1,008.54x = 1,391.58 × 615.69
4. Step 4: Simplify right side
   1,008.54x = 856,781.89
5. Step 5: Solve for x
   x = 856,781.89/1,008.54
6. Step 6: Final answer
   x = 849.53