Finding the Fourth Proportional to 12,279.89, 18,420.50 and 3,960.57

Step by Step Solution

1. Step 1: Write the proportion equation
   12,279.89 : 18,420.50 = 3,960.57 : x
2. Step 2: Convert to fraction form
   12,279.89/18,420.50 = 3,960.57/x
3. Step 3: Cross multiply
   12,279.89x = 18,420.50 × 3,960.57
4. Step 4: Simplify right side
   12,279.89x = 72,955,659.88
5. Step 5: Solve for x
   x = 72,955,659.88/12,279.89
6. Step 6: Final answer
   x = 5,941.07