Finding the Fourth Proportional to 12,139.32, 18,201.45 and 5,115.72

Step by Step Solution

1. Step 1: Write the proportion equation
   12,139.32 : 18,201.45 = 5,115.72 : x
2. Step 2: Convert to fraction form
   12,139.32/18,201.45 = 5,115.72/x
3. Step 3: Cross multiply
   12,139.32x = 18,201.45 × 5,115.72
4. Step 4: Simplify right side
   12,139.32x = 93,113,521.79
5. Step 5: Solve for x
   x = 93,113,521.79/12,139.32
6. Step 6: Final answer
   x = 7,670.41