Finding the Third Proportional to 120,689 and 257,404

Step by Step Solution

1. Step 1: Write the proportion equation
   120,689 : 257,404 = 257,404 : x
2. Step 2: Convert to fraction form
   120,689/257,404 = 257,404/x
3. Step 3: Cross multiply
   120,689x = 257,404 × 257,404
4. Step 4: Simplify right side
   120,689x = 66,256,819,216
5. Step 5: Solve for x
   x = 66,256,819,216/120,689
6. Step 6: Final answer
   x = 548,988.05