Finding the Fourth Proportional to 11,921.47, 17,885.16 and 8,418.34

Step by Step Solution

1. Step 1: Write the proportion equation
   11,921.47 : 17,885.16 = 8,418.34 : x
2. Step 2: Convert to fraction form
   11,921.47/17,885.16 = 8,418.34/x
3. Step 3: Cross multiply
   11,921.47x = 17,885.16 × 8,418.34
4. Step 4: Simplify right side
   11,921.47x = 150,563,357.83
5. Step 5: Solve for x
   x = 150,563,357.83/11,921.47
6. Step 6: Final answer
   x = 12,629.60