Finding the Third Proportional to 138,780 and 298,608

Step by Step Solution

1. Step 1: Write the proportion equation
   138,780 : 298,608 = 298,608 : x
2. Step 2: Convert to fraction form
   138,780/298,608 = 298,608/x
3. Step 3: Cross multiply
   138,780x = 298,608 × 298,608
4. Step 4: Simplify right side
   138,780x = 89,166,737,664
5. Step 5: Solve for x
   x = 89,166,737,664/138,780
6. Step 6: Final answer
   x = 642,504.23