Finding the Fourth Proportional to 9,915.10, 13,681.96 and 5,665.31

Step by Step Solution

1. Step 1: Write the proportion equation
   9,915.10 : 13,681.96 = 5,665.31 : x
2. Step 2: Convert to fraction form
   9,915.10/13,681.96 = 5,665.31/x
3. Step 3: Cross multiply
   9,915.10x = 13,681.96 × 5,665.31
4. Step 4: Simplify right side
   9,915.10x = 77,512,545.41
5. Step 5: Solve for x
   x = 77,512,545.41/9,915.10
6. Step 6: Final answer
   x = 7,817.63