Finding the Fourth Proportional to 5,408.78, 8,065.42 and 5,216.04

Step by Step Solution

1. Step 1: Write the proportion equation
   5,408.78 : 8,065.42 = 5,216.04 : x
2. Step 2: Convert to fraction form
   5,408.78/8,065.42 = 5,216.04/x
3. Step 3: Cross multiply
   5,408.78x = 8,065.42 × 5,216.04
4. Step 4: Simplify right side
   5,408.78x = 42,069,540.30
5. Step 5: Solve for x
   x = 42,069,540.30/5,408.78
6. Step 6: Final answer
   x = 7,778.02