Finding the Third Proportional to 258,689.50 and 386,441

Step by Step Solution

1. Step 1: Write the proportion equation
   258,689.50 : 386,441 = 386,441 : x
2. Step 2: Convert to fraction form
   258,689.50/386,441 = 386,441/x
3. Step 3: Cross multiply
   258,689.50x = 386,441 × 386,441
4. Step 4: Simplify right side
   258,689.50x = 149,336,646,481
5. Step 5: Solve for x
   x = 149,336,646,481/258,689.50
6. Step 6: Final answer
   x = 577,281.44