Finding the Third Proportional to 31,990 and 67,671

Step by Step Solution

1. Step 1: Write the proportion equation
   31,990 : 67,671 = 67,671 : x
2. Step 2: Convert to fraction form
   31,990/67,671 = 67,671/x
3. Step 3: Cross multiply
   31,990x = 67,671 × 67,671
4. Step 4: Simplify right side
   31,990x = 4,579,364,241
5. Step 5: Solve for x
   x = 4,579,364,241/31,990
6. Step 6: Final answer
   x = 143,149.87