Finding the Third Proportional to 357,209 and 485,129.50

Step by Step Solution

1. Step 1: Write the proportion equation
   357,209 : 485,129.50 = 485,129.50 : x
2. Step 2: Convert to fraction form
   357,209/485,129.50 = 485,129.50/x
3. Step 3: Cross multiply
   357,209x = 485,129.50 × 485,129.50
4. Step 4: Simplify right side
   357,209x = 235,350,631,770.25
5. Step 5: Solve for x
   x = 235,350,631,770.25/357,209
6. Step 6: Final answer
   x = 658,859.75