Finding the Third Proportional to 78,912,686 and 172,910,812

Step by Step Solution

1. Step 1: Write the proportion equation
   78,912,686 : 172,910,812 = 172,910,812 : x
2. Step 2: Convert to fraction form
   78,912,686/172,910,812 = 172,910,812/x
3. Step 3: Cross multiply
   78,912,686x = 172,910,812 × 172,910,812
4. Step 4: Simplify right side
   78,912,686x = 29,898,148,906,499,344
5. Step 5: Solve for x
   x = 29,898,148,906,499,344/78,912,686
6. Step 6: Final answer
   x = 378,876,330.56