Finding the Fourth Proportional to 9,408.38, 12,980.61 and 5,428.97

Step by Step Solution

1. Step 1: Write the proportion equation
   9,408.38 : 12,980.61 = 5,428.97 : x
2. Step 2: Convert to fraction form
   9,408.38/12,980.61 = 5,428.97/x
3. Step 3: Cross multiply
   9,408.38x = 12,980.61 × 5,428.97
4. Step 4: Simplify right side
   9,408.38x = 70,471,342.27
5. Step 5: Solve for x
   x = 70,471,342.27/9,408.38
6. Step 6: Final answer
   x = 7,490.27