Finding the Fourth Proportional to 31,067.28, 42,872.90 and 16,920.18

Step by Step Solution

1. Step 1: Write the proportion equation
   31,067.28 : 42,872.90 = 16,920.18 : x
2. Step 2: Convert to fraction form
   31,067.28/42,872.90 = 16,920.18/x
3. Step 3: Cross multiply
   31,067.28x = 42,872.90 × 16,920.18
4. Step 4: Simplify right side
   31,067.28x = 725,417,100.52
5. Step 5: Solve for x
   x = 725,417,100.52/31,067.28
6. Step 6: Final answer
   x = 23,349.87