Finding the Third Proportional to 138,639 and 198,109.50

Step by Step Solution

1. Step 1: Write the proportion equation
   138,639 : 198,109.50 = 198,109.50 : x
2. Step 2: Convert to fraction form
   138,639/198,109.50 = 198,109.50/x
3. Step 3: Cross multiply
   138,639x = 198,109.50 × 198,109.50
4. Step 4: Simplify right side
   138,639x = 39,247,373,990.25
5. Step 5: Solve for x
   x = 39,247,373,990.25/138,639
6. Step 6: Final answer
   x = 283,090.43