Finding the Fourth Proportional to 31,115, 42,923.90 and 21,046.96

Step by Step Solution

1. Step 1: Write the proportion equation
   31,115 : 42,923.90 = 21,046.96 : x
2. Step 2: Convert to fraction form
   31,115/42,923.90 = 21,046.96/x
3. Step 3: Cross multiply
   31,115x = 42,923.90 × 21,046.96
4. Step 4: Simplify right side
   31,115x = 903,417,606.34
5. Step 5: Solve for x
   x = 903,417,606.34/31,115
6. Step 6: Final answer
   x = 29,034.79