Finding the Fourth Proportional to 21,137.24, 31,719.69 and 7,989.62

Step by Step Solution

1. Step 1: Write the proportion equation
   21,137.24 : 31,719.69 = 7,989.62 : x
2. Step 2: Convert to fraction form
   21,137.24/31,719.69 = 7,989.62/x
3. Step 3: Cross multiply
   21,137.24x = 31,719.69 × 7,989.62
4. Step 4: Simplify right side
   21,137.24x = 253,428,111.02
5. Step 5: Solve for x
   x = 253,428,111.02/21,137.24
6. Step 6: Final answer
   x = 11,989.65