Finding the Fourth Proportional to 9,402.89, 12,978.84 and 5,426.60

Step by Step Solution

1. Step 1: Write the proportion equation
   9,402.89 : 12,978.84 = 5,426.60 : x
2. Step 2: Convert to fraction form
   9,402.89/12,978.84 = 5,426.60/x
3. Step 3: Cross multiply
   9,402.89x = 12,978.84 × 5,426.60
4. Step 4: Simplify right side
   9,402.89x = 70,430,908.25
5. Step 5: Solve for x
   x = 70,430,908.25/9,402.89
6. Step 6: Final answer
   x = 7,490.35