Finding the Fourth Proportional to 21,259.59, 31,891.55 and 5,678.31

Step by Step Solution

1. Step 1: Write the proportion equation
   21,259.59 : 31,891.55 = 5,678.31 : x
2. Step 2: Convert to fraction form
   21,259.59/31,891.55 = 5,678.31/x
3. Step 3: Cross multiply
   21,259.59x = 31,891.55 × 5,678.31
4. Step 4: Simplify right side
   21,259.59x = 181,090,078.89
5. Step 5: Solve for x
   x = 181,090,078.89/21,259.59
6. Step 6: Final answer
   x = 8,518.04