Finding the Fourth Proportional to 12,321.18, 18,479.61 and 3,999.98

Step by Step Solution

1. Step 1: Write the proportion equation
   12,321.18 : 18,479.61 = 3,999.98 : x
2. Step 2: Convert to fraction form
   12,321.18/18,479.61 = 3,999.98/x
3. Step 3: Cross multiply
   12,321.18x = 18,479.61 × 3,999.98
4. Step 4: Simplify right side
   12,321.18x = 73,918,116.61
5. Step 5: Solve for x
   x = 73,918,116.61/12,321.18
6. Step 6: Final answer
   x = 5,999.27