Finding the Fourth Proportional to 21,002.28, 31,499.10 and 9,904.20

Step by Step Solution

1. Step 1: Write the proportion equation
   21,002.28 : 31,499.10 = 9,904.20 : x
2. Step 2: Convert to fraction form
   21,002.28/31,499.10 = 9,904.20/x
3. Step 3: Cross multiply
   21,002.28x = 31,499.10 × 9,904.20
4. Step 4: Simplify right side
   21,002.28x = 311,973,386.22
5. Step 5: Solve for x
   x = 311,973,386.22/21,002.28
6. Step 6: Final answer
   x = 14,854.26