Finding the Fourth Proportional to 8,418.73, 12,528.72 and 8,138.43

Step by Step Solution

1. Step 1: Write the proportion equation
   8,418.73 : 12,528.72 = 8,138.43 : x
2. Step 2: Convert to fraction form
   8,418.73/12,528.72 = 8,138.43/x
3. Step 3: Cross multiply
   8,418.73x = 12,528.72 × 8,138.43
4. Step 4: Simplify right side
   8,418.73x = 101,964,110.71
5. Step 5: Solve for x
   x = 101,964,110.71/8,418.73
6. Step 6: Final answer
   x = 12,111.58