Finding the Fourth Proportional to 12,138.69, 18,204.78 and 5,118.75

Step by Step Solution

1. Step 1: Write the proportion equation
   12,138.69 : 18,204.78 = 5,118.75 : x
2. Step 2: Convert to fraction form
   12,138.69/18,204.78 = 5,118.75/x
3. Step 3: Cross multiply
   12,138.69x = 18,204.78 × 5,118.75
4. Step 4: Simplify right side
   12,138.69x = 93,185,717.63
5. Step 5: Solve for x
   x = 93,185,717.63/12,138.69
6. Step 6: Final answer
   x = 7,676.75