Finding the Fourth Proportional to 12,308.29, 18,464.43 and 3,990.40

Step by Step Solution

1. Step 1: Write the proportion equation
   12,308.29 : 18,464.43 = 3,990.40 : x
2. Step 2: Convert to fraction form
   12,308.29/18,464.43 = 3,990.40/x
3. Step 3: Cross multiply
   12,308.29x = 18,464.43 × 3,990.40
4. Step 4: Simplify right side
   12,308.29x = 73,680,461.47
5. Step 5: Solve for x
   x = 73,680,461.47/12,308.29
6. Step 6: Final answer
   x = 5,986.25