Finding the Fourth Proportional to 31,721.07, 43,755.27 and 20,405.31

Step by Step Solution

1. Step 1: Write the proportion equation
   31,721.07 : 43,755.27 = 20,405.31 : x
2. Step 2: Convert to fraction form
   31,721.07/43,755.27 = 20,405.31/x
3. Step 3: Cross multiply
   31,721.07x = 43,755.27 × 20,405.31
4. Step 4: Simplify right side
   31,721.07x = 892,839,848.48
5. Step 5: Solve for x
   x = 892,839,848.48/31,721.07
6. Step 6: Final answer
   x = 28,146.59