Finding the Fourth Proportional to 9,771.31, 13,485.32 and 5,578.75

Step by Step Solution

1. Step 1: Write the proportion equation
   9,771.31 : 13,485.32 = 5,578.75 : x
2. Step 2: Convert to fraction form
   9,771.31/13,485.32 = 5,578.75/x
3. Step 3: Cross multiply
   9,771.31x = 13,485.32 × 5,578.75
4. Step 4: Simplify right side
   9,771.31x = 75,231,228.95
5. Step 5: Solve for x
   x = 75,231,228.95/9,771.31
6. Step 6: Final answer
   x = 7,699.20