Finding the Third Proportional to 256,516.50 and 394,860

Step by Step Solution

1. Step 1: Write the proportion equation
   256,516.50 : 394,860 = 394,860 : x
2. Step 2: Convert to fraction form
   256,516.50/394,860 = 394,860/x
3. Step 3: Cross multiply
   256,516.50x = 394,860 × 394,860
4. Step 4: Simplify right side
   256,516.50x = 155,914,419,600
5. Step 5: Solve for x
   x = 155,914,419,600/256,516.50
6. Step 6: Final answer
   x = 607,814.39