Finding the Fourth Proportional to 9,619.78, 13,281.42 and 7,855.60

Step by Step Solution

1. Step 1: Write the proportion equation
   9,619.78 : 13,281.42 = 7,855.60 : x
2. Step 2: Convert to fraction form
   9,619.78/13,281.42 = 7,855.60/x
3. Step 3: Cross multiply
   9,619.78x = 13,281.42 × 7,855.60
4. Step 4: Simplify right side
   9,619.78x = 104,333,522.95
5. Step 5: Solve for x
   x = 104,333,522.95/9,619.78
6. Step 6: Final answer
   x = 10,845.73