Finding the Fourth Proportional to 13,404.43, 18,521.13 and 12,931.39

Step by Step Solution

1. Step 1: Write the proportion equation
   13,404.43 : 18,521.13 = 12,931.39 : x
2. Step 2: Convert to fraction form
   13,404.43/18,521.13 = 12,931.39/x
3. Step 3: Cross multiply
   13,404.43x = 18,521.13 × 12,931.39
4. Step 4: Simplify right side
   13,404.43x = 239,503,955.27
5. Step 5: Solve for x
   x = 239,503,955.27/13,404.43
6. Step 6: Final answer
   x = 17,867.52