Finding the Fourth Proportional to 21,013.89, 31,519.92 and 5,218.55

Step by Step Solution

1. Step 1: Write the proportion equation
   21,013.89 : 31,519.92 = 5,218.55 : x
2. Step 2: Convert to fraction form
   21,013.89/31,519.92 = 5,218.55/x
3. Step 3: Cross multiply
   21,013.89x = 31,519.92 × 5,218.55
4. Step 4: Simplify right side
   21,013.89x = 164,488,278.52
5. Step 5: Solve for x
   x = 164,488,278.52/21,013.89
6. Step 6: Final answer
   x = 7,827.60