Finding the Third Proportional to 258,123 and 398,740.50

Step by Step Solution

1. Step 1: Write the proportion equation
   258,123 : 398,740.50 = 398,740.50 : x
2. Step 2: Convert to fraction form
   258,123/398,740.50 = 398,740.50/x
3. Step 3: Cross multiply
   258,123x = 398,740.50 × 398,740.50
4. Step 4: Simplify right side
   258,123x = 158,993,986,340.25
5. Step 5: Solve for x
   x = 158,993,986,340.25/258,123
6. Step 6: Final answer
   x = 615,962.10