Finding the Third Proportional to 20,921 and 31,872

Step by Step Solution

1. Step 1: Write the proportion equation
   20,921 : 31,872 = 31,872 : x
2. Step 2: Convert to fraction form
   20,921/31,872 = 31,872/x
3. Step 3: Cross multiply
   20,921x = 31,872 × 31,872
4. Step 4: Simplify right side
   20,921x = 1,015,824,384
5. Step 5: Solve for x
   x = 1,015,824,384/20,921
6. Step 6: Final answer
   x = 48,555.25