Finding the Fourth Proportional to 9,405.92, 12,978.36 and 5,427.20

Step by Step Solution

1. Step 1: Write the proportion equation
   9,405.92 : 12,978.36 = 5,427.20 : x
2. Step 2: Convert to fraction form
   9,405.92/12,978.36 = 5,427.20/x
3. Step 3: Cross multiply
   9,405.92x = 12,978.36 × 5,427.20
4. Step 4: Simplify right side
   9,405.92x = 70,436,155.39
5. Step 5: Solve for x
   x = 70,436,155.39/9,405.92
6. Step 6: Final answer
   x = 7,488.49