Finding the Third Proportional to 31,920 and 68,644.50

Step by Step Solution

1. Step 1: Write the proportion equation
   31,920 : 68,644.50 = 68,644.50 : x
2. Step 2: Convert to fraction form
   31,920/68,644.50 = 68,644.50/x
3. Step 3: Cross multiply
   31,920x = 68,644.50 × 68,644.50
4. Step 4: Simplify right side
   31,920x = 4,712,067,380.25
5. Step 5: Solve for x
   x = 4,712,067,380.25/31,920
6. Step 6: Final answer
   x = 147,621.16