Finding the Fourth Proportional to 31,105.04, 42,930.27 and 21,558.78

Step by Step Solution

1. Step 1: Write the proportion equation
   31,105.04 : 42,930.27 = 21,558.78 : x
2. Step 2: Convert to fraction form
   31,105.04/42,930.27 = 21,558.78/x
3. Step 3: Cross multiply
   31,105.04x = 42,930.27 × 21,558.78
4. Step 4: Simplify right side
   31,105.04x = 925,524,246.27
5. Step 5: Solve for x
   x = 925,524,246.27/31,105.04
6. Step 6: Final answer
   x = 29,754.80