Finding the Fourth Proportional to 13,121.47, 18,111.52 and 12,451.80

Step by Step Solution

1. Step 1: Write the proportion equation
   13,121.47 : 18,111.52 = 12,451.80 : x
2. Step 2: Convert to fraction form
   13,121.47/18,111.52 = 12,451.80/x
3. Step 3: Cross multiply
   13,121.47x = 18,111.52 × 12,451.80
4. Step 4: Simplify right side
   13,121.47x = 225,521,092.30
5. Step 5: Solve for x
   x = 225,521,092.30/13,121.47
6. Step 6: Final answer
   x = 17,187.18