Finding the Third Proportional to 258,414 and 548,139

Step by Step Solution

1. Step 1: Write the proportion equation
   258,414 : 548,139 = 548,139 : x
2. Step 2: Convert to fraction form
   258,414/548,139 = 548,139/x
3. Step 3: Cross multiply
   258,414x = 548,139 × 548,139
4. Step 4: Simplify right side
   258,414x = 300,456,363,321
5. Step 5: Solve for x
   x = 300,456,363,321/258,414
6. Step 6: Final answer
   x = 1,162,693.83