Finding the Third Proportional to 86,158.50 and 128,721.38

Step by Step Solution

1. Step 1: Write the proportion equation
   86,158.50 : 128,721.38 = 128,721.38 : x
2. Step 2: Convert to fraction form
   86,158.50/128,721.38 = 128,721.38/x
3. Step 3: Cross multiply
   86,158.50x = 128,721.38 × 128,721.38
4. Step 4: Simplify right side
   86,158.50x = 16,569,192,381.89
5. Step 5: Solve for x
   x = 16,569,192,381.89/86,158.50
6. Step 6: Final answer
   x = 192,310.59