Finding the Fourth Proportional to 21,089.76, 31,639.34 and 7,942.24

Step by Step Solution

1. Step 1: Write the proportion equation
   21,089.76 : 31,639.34 = 7,942.24 : x
2. Step 2: Convert to fraction form
   21,089.76/31,639.34 = 7,942.24/x
3. Step 3: Cross multiply
   21,089.76x = 31,639.34 × 7,942.24
4. Step 4: Simplify right side
   21,089.76x = 251,287,231.72
5. Step 5: Solve for x
   x = 251,287,231.72/21,089.76
6. Step 6: Final answer
   x = 11,915.13