Finding the Third Proportional to 90,408 and 139,872

Step by Step Solution

1. Step 1: Write the proportion equation
   90,408 : 139,872 = 139,872 : x
2. Step 2: Convert to fraction form
   90,408/139,872 = 139,872/x
3. Step 3: Cross multiply
   90,408x = 139,872 × 139,872
4. Step 4: Simplify right side
   90,408x = 19,564,176,384
5. Step 5: Solve for x
   x = 19,564,176,384/90,408
6. Step 6: Final answer
   x = 216,398.73