Finding the Third Proportional to 257,707.50 and 387,046.50

Step by Step Solution

1. Step 1: Write the proportion equation
   257,707.50 : 387,046.50 = 387,046.50 : x
2. Step 2: Convert to fraction form
   257,707.50/387,046.50 = 387,046.50/x
3. Step 3: Cross multiply
   257,707.50x = 387,046.50 × 387,046.50
4. Step 4: Simplify right side
   257,707.50x = 149,804,993,162.25
5. Step 5: Solve for x
   x = 149,804,993,162.25/257,707.50
6. Step 6: Final answer
   x = 581,298.54