Finding the Fourth Proportional to 9,915.78, 13,683.78 and 5,439.62

Step by Step Solution

1. Step 1: Write the proportion equation
   9,915.78 : 13,683.78 = 5,439.62 : x
2. Step 2: Convert to fraction form
   9,915.78/13,683.78 = 5,439.62/x
3. Step 3: Cross multiply
   9,915.78x = 13,683.78 × 5,439.62
4. Step 4: Simplify right side
   9,915.78x = 74,434,494.94
5. Step 5: Solve for x
   x = 74,434,494.94/9,915.78
6. Step 6: Final answer
   x = 7,506.67