Finding the Fourth Proportional to 21,005.66, 31,504.81 and 7,855.31

Step by Step Solution

1. Step 1: Write the proportion equation
   21,005.66 : 31,504.81 = 7,855.31 : x
2. Step 2: Convert to fraction form
   21,005.66/31,504.81 = 7,855.31/x
3. Step 3: Cross multiply
   21,005.66x = 31,504.81 × 7,855.31
4. Step 4: Simplify right side
   21,005.66x = 247,480,049.04
5. Step 5: Solve for x
   x = 247,480,049.04/21,005.66
6. Step 6: Final answer
   x = 11,781.59