Finding the Third Proportional to 122,499 and 288,217.50

Step by Step Solution

1. Step 1: Write the proportion equation
   122,499 : 288,217.50 = 288,217.50 : x
2. Step 2: Convert to fraction form
   122,499/288,217.50 = 288,217.50/x
3. Step 3: Cross multiply
   122,499x = 288,217.50 × 288,217.50
4. Step 4: Simplify right side
   122,499x = 83,069,327,306.25
5. Step 5: Solve for x
   x = 83,069,327,306.25/122,499
6. Step 6: Final answer
   x = 678,122.49