Finding the Fourth Proportional to 8,815.59, 13,131.76 and 8,338.12

Step by Step Solution

1. Step 1: Write the proportion equation
   8,815.59 : 13,131.76 = 8,338.12 : x
2. Step 2: Convert to fraction form
   8,815.59/13,131.76 = 8,338.12/x
3. Step 3: Cross multiply
   8,815.59x = 13,131.76 × 8,338.12
4. Step 4: Simplify right side
   8,815.59x = 109,494,249.97
5. Step 5: Solve for x
   x = 109,494,249.97/8,815.59
6. Step 6: Final answer
   x = 12,420.52