Finding the Third Proportional to 78,707,123 and 172,909,869

Step by Step Solution

1. Step 1: Write the proportion equation
   78,707,123 : 172,909,869 = 172,909,869 : x
2. Step 2: Convert to fraction form
   78,707,123/172,909,869 = 172,909,869/x
3. Step 3: Cross multiply
   78,707,123x = 172,909,869 × 172,909,869
4. Step 4: Simplify right side
   78,707,123x = 29,897,822,797,597,160
5. Step 5: Solve for x
   x = 29,897,822,797,597,160/78,707,123
6. Step 6: Final answer
   x = 379,861,715.92