Finding the Third Proportional to 616.78 and 865.27

Step by Step Solution

1. Step 1: Write the proportion equation
   616.78 : 865.27 = 865.27 : x
2. Step 2: Convert to fraction form
   616.78/865.27 = 865.27/x
3. Step 3: Cross multiply
   616.78x = 865.27 × 865.27
4. Step 4: Simplify right side
   616.78x = 748,684.60
5. Step 5: Solve for x
   x = 748,684.60/616.78
6. Step 6: Final answer
   x = 1,213.86