Finding the Fourth Proportional to 1,009.72, 1,393.59 and 616.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,009.72 : 1,393.59 = 616.96 : x
2. Step 2: Convert to fraction form
   1,009.72/1,393.59 = 616.96/x
3. Step 3: Cross multiply
   1,009.72x = 1,393.59 × 616.96
4. Step 4: Simplify right side
   1,009.72x = 859,789.29
5. Step 5: Solve for x
   x = 859,789.29/1,009.72
6. Step 6: Final answer
   x = 851.51