Finding the Third Proportional to 31,721 and 68,910

Step by Step Solution

1. Step 1: Write the proportion equation
   31,721 : 68,910 = 68,910 : x
2. Step 2: Convert to fraction form
   31,721/68,910 = 68,910/x
3. Step 3: Cross multiply
   31,721x = 68,910 × 68,910
4. Step 4: Simplify right side
   31,721x = 4,748,588,100
5. Step 5: Solve for x
   x = 4,748,588,100/31,721
6. Step 6: Final answer
   x = 149,698.56