Finding the Third Proportional to 31,720.50 and 68,910.75

Step by Step Solution

1. Step 1: Write the proportion equation
   31,720.50 : 68,910.75 = 68,910.75 : x
2. Step 2: Convert to fraction form
   31,720.50/68,910.75 = 68,910.75/x
3. Step 3: Cross multiply
   31,720.50x = 68,910.75 × 68,910.75
4. Step 4: Simplify right side
   31,720.50x = 4,748,691,465.56
5. Step 5: Solve for x
   x = 4,748,691,465.56/31,720.50
6. Step 6: Final answer
   x = 149,704.18