Finding the Fourth Proportional to 31,140.72, 42,974.28 and 18,565.20

Step by Step Solution

1. Step 1: Write the proportion equation
   31,140.72 : 42,974.28 = 18,565.20 : x
2. Step 2: Convert to fraction form
   31,140.72/42,974.28 = 18,565.20/x
3. Step 3: Cross multiply
   31,140.72x = 42,974.28 × 18,565.20
4. Step 4: Simplify right side
   31,140.72x = 797,826,103.06
5. Step 5: Solve for x
   x = 797,826,103.06/31,140.72
6. Step 6: Final answer
   x = 25,620.03