Finding the Fourth Proportional to 12,665.91, 18,999.12 and 3,900.82

Step by Step Solution

1. Step 1: Write the proportion equation
   12,665.91 : 18,999.12 = 3,900.82 : x
2. Step 2: Convert to fraction form
   12,665.91/18,999.12 = 3,900.82/x
3. Step 3: Cross multiply
   12,665.91x = 18,999.12 × 3,900.82
4. Step 4: Simplify right side
   12,665.91x = 74,112,052.28
5. Step 5: Solve for x
   x = 74,112,052.28/12,665.91
6. Step 6: Final answer
   x = 5,851.30