Finding the Third Proportional to 280,478 and 435,123

Step by Step Solution

1. Step 1: Write the proportion equation
   280,478 : 435,123 = 435,123 : x
2. Step 2: Convert to fraction form
   280,478/435,123 = 435,123/x
3. Step 3: Cross multiply
   280,478x = 435,123 × 435,123
4. Step 4: Simplify right side
   280,478x = 189,332,025,129
5. Step 5: Solve for x
   x = 189,332,025,129/280,478
6. Step 6: Final answer
   x = 675,033.43