Finding the Fourth Proportional to 31,150.63, 42,974.85 and 20,398.15

Step by Step Solution

1. Step 1: Write the proportion equation
   31,150.63 : 42,974.85 = 20,398.15 : x
2. Step 2: Convert to fraction form
   31,150.63/42,974.85 = 20,398.15/x
3. Step 3: Cross multiply
   31,150.63x = 42,974.85 × 20,398.15
4. Step 4: Simplify right side
   31,150.63x = 876,607,436.53
5. Step 5: Solve for x
   x = 876,607,436.53/31,150.63
6. Step 6: Final answer
   x = 28,140.92