Finding the Fourth Proportional to 8,978.55, 12,391.48 and 5,395.51

Step by Step Solution

1. Step 1: Write the proportion equation
   8,978.55 : 12,391.48 = 5,395.51 : x
2. Step 2: Convert to fraction form
   8,978.55/12,391.48 = 5,395.51/x
3. Step 3: Cross multiply
   8,978.55x = 12,391.48 × 5,395.51
4. Step 4: Simplify right side
   8,978.55x = 66,858,376.49
5. Step 5: Solve for x
   x = 66,858,376.49/8,978.55
6. Step 6: Final answer
   x = 7,446.46