Finding the Third Proportional to 89,978 and 139,683

Step by Step Solution

1. Step 1: Write the proportion equation
   89,978 : 139,683 = 139,683 : x
2. Step 2: Convert to fraction form
   89,978/139,683 = 139,683/x
3. Step 3: Cross multiply
   89,978x = 139,683 × 139,683
4. Step 4: Simplify right side
   89,978x = 19,511,340,489
5. Step 5: Solve for x
   x = 19,511,340,489/89,978
6. Step 6: Final answer
   x = 216,845.68