Finding the Fourth Proportional to 12,279.56, 18,421.97 and 3,960.05

Step by Step Solution

1. Step 1: Write the proportion equation
   12,279.56 : 18,421.97 = 3,960.05 : x
2. Step 2: Convert to fraction form
   12,279.56/18,421.97 = 3,960.05/x
3. Step 3: Cross multiply
   12,279.56x = 18,421.97 × 3,960.05
4. Step 4: Simplify right side
   12,279.56x = 72,951,810.39
5. Step 5: Solve for x
   x = 72,951,810.39/12,279.56
6. Step 6: Final answer
   x = 5,940.92