Finding the Third Proportional to 120,658.50 and 259,816.50

Step by Step Solution

1. Step 1: Write the proportion equation
   120,658.50 : 259,816.50 = 259,816.50 : x
2. Step 2: Convert to fraction form
   120,658.50/259,816.50 = 259,816.50/x
3. Step 3: Cross multiply
   120,658.50x = 259,816.50 × 259,816.50
4. Step 4: Simplify right side
   120,658.50x = 67,504,613,672.25
5. Step 5: Solve for x
   x = 67,504,613,672.25/120,658.50
6. Step 6: Final answer
   x = 559,468.36