Finding the Fourth Proportional to 12,939.80, 17,846.46 and 8,689.58

Step by Step Solution

1. Step 1: Write the proportion equation
   12,939.80 : 17,846.46 = 8,689.58 : x
2. Step 2: Convert to fraction form
   12,939.80/17,846.46 = 8,689.58/x
3. Step 3: Cross multiply
   12,939.80x = 17,846.46 × 8,689.58
4. Step 4: Simplify right side
   12,939.80x = 155,078,241.89
5. Step 5: Solve for x
   x = 155,078,241.89/12,939.80
6. Step 6: Final answer
   x = 11,984.59