Finding the Fourth Proportional to 21,046.76, 31,560.42 and 7,889.72

Step by Step Solution

1. Step 1: Write the proportion equation
   21,046.76 : 31,560.42 = 7,889.72 : x
2. Step 2: Convert to fraction form
   21,046.76/31,560.42 = 7,889.72/x
3. Step 3: Cross multiply
   21,046.76x = 31,560.42 × 7,889.72
4. Step 4: Simplify right side
   21,046.76x = 249,002,876.88
5. Step 5: Solve for x
   x = 249,002,876.88/21,046.76
6. Step 6: Final answer
   x = 11,830.94