Finding the Fourth Proportional to 9,866.39, 13,615.38 and 5,390.15

Step by Step Solution

1. Step 1: Write the proportion equation
   9,866.39 : 13,615.38 = 5,390.15 : x
2. Step 2: Convert to fraction form
   9,866.39/13,615.38 = 5,390.15/x
3. Step 3: Cross multiply
   9,866.39x = 13,615.38 × 5,390.15
4. Step 4: Simplify right side
   9,866.39x = 73,388,872.43
5. Step 5: Solve for x
   x = 73,388,872.43/9,866.39
6. Step 6: Final answer
   x = 7,438.27