Finding the Fourth Proportional to 8,665.89, 12,988.03 and 3,980.92

Step by Step Solution

1. Step 1: Write the proportion equation
   8,665.89 : 12,988.03 = 3,980.92 : x
2. Step 2: Convert to fraction form
   8,665.89/12,988.03 = 3,980.92/x
3. Step 3: Cross multiply
   8,665.89x = 12,988.03 × 3,980.92
4. Step 4: Simplify right side
   8,665.89x = 51,704,308.39
5. Step 5: Solve for x
   x = 51,704,308.39/8,665.89
6. Step 6: Final answer
   x = 5,966.42