Finding the Fourth Proportional to 21,142.12, 31,716.78 and 7,287.88

Step by Step Solution

1. Step 1: Write the proportion equation
   21,142.12 : 31,716.78 = 7,287.88 : x
2. Step 2: Convert to fraction form
   21,142.12/31,716.78 = 7,287.88/x
3. Step 3: Cross multiply
   21,142.12x = 31,716.78 × 7,287.88
4. Step 4: Simplify right side
   21,142.12x = 231,147,891.60
5. Step 5: Solve for x
   x = 231,147,891.60/21,142.12
6. Step 6: Final answer
   x = 10,933.05