Finding the Fourth Proportional to 31,067.99, 42,879.38 and 18,320.40

Step by Step Solution

1. Step 1: Write the proportion equation
   31,067.99 : 42,879.38 = 18,320.40 : x
2. Step 2: Convert to fraction form
   31,067.99/42,879.38 = 18,320.40/x
3. Step 3: Cross multiply
   31,067.99x = 42,879.38 × 18,320.40
4. Step 4: Simplify right side
   31,067.99x = 785,567,266.94
5. Step 5: Solve for x
   x = 785,567,266.94/31,067.99
6. Step 6: Final answer
   x = 25,285.43