Finding the Fourth Proportional to 9,399.88, 12,942.32 and 7,980.62

Step by Step Solution

1. Step 1: Write the proportion equation
   9,399.88 : 12,942.32 = 7,980.62 : x
2. Step 2: Convert to fraction form
   9,399.88/12,942.32 = 7,980.62/x
3. Step 3: Cross multiply
   9,399.88x = 12,942.32 × 7,980.62
4. Step 4: Simplify right side
   9,399.88x = 103,287,737.84
5. Step 5: Solve for x
   x = 103,287,737.84/9,399.88
6. Step 6: Final answer
   x = 10,988.20