Finding the Fourth Proportional to 13,146.43, 18,131.79 and 8,431.15

Step by Step Solution

1. Step 1: Write the proportion equation
   13,146.43 : 18,131.79 = 8,431.15 : x
2. Step 2: Convert to fraction form
   13,146.43/18,131.79 = 8,431.15/x
3. Step 3: Cross multiply
   13,146.43x = 18,131.79 × 8,431.15
4. Step 4: Simplify right side
   13,146.43x = 152,871,841.26
5. Step 5: Solve for x
   x = 152,871,841.26/13,146.43
6. Step 6: Final answer
   x = 11,628.39