Finding the Fourth Proportional to 31,021.20, 42,816.06 and 20,411.82

Step by Step Solution

1. Step 1: Write the proportion equation
   31,021.20 : 42,816.06 = 20,411.82 : x
2. Step 2: Convert to fraction form
   31,021.20/42,816.06 = 20,411.82/x
3. Step 3: Cross multiply
   31,021.20x = 42,816.06 × 20,411.82
4. Step 4: Simplify right side
   31,021.20x = 873,953,709.83
5. Step 5: Solve for x
   x = 873,953,709.83/31,021.20
6. Step 6: Final answer
   x = 28,172.79