Finding the Fourth Proportional to 9,915.28, 13,656.81 and 7,389.31

Step by Step Solution

1. Step 1: Write the proportion equation
   9,915.28 : 13,656.81 = 7,389.31 : x
2. Step 2: Convert to fraction form
   9,915.28/13,656.81 = 7,389.31/x
3. Step 3: Cross multiply
   9,915.28x = 13,656.81 × 7,389.31
4. Step 4: Simplify right side
   9,915.28x = 100,914,402.70
5. Step 5: Solve for x
   x = 100,914,402.70/9,915.28
6. Step 6: Final answer
   x = 10,177.67