Finding the Third Proportional to 81,099 and 129,142.50

Step by Step Solution

1. Step 1: Write the proportion equation
   81,099 : 129,142.50 = 129,142.50 : x
2. Step 2: Convert to fraction form
   81,099/129,142.50 = 129,142.50/x
3. Step 3: Cross multiply
   81,099x = 129,142.50 × 129,142.50
4. Step 4: Simplify right side
   81,099x = 16,677,785,306.25
5. Step 5: Solve for x
   x = 16,677,785,306.25/81,099
6. Step 6: Final answer
   x = 205,647.24