Finding the Fourth Proportional to 11,321.57, 15,638.73 and 9,439.31

Step by Step Solution

1. Step 1: Write the proportion equation
   11,321.57 : 15,638.73 = 9,439.31 : x
2. Step 2: Convert to fraction form
   11,321.57/15,638.73 = 9,439.31/x
3. Step 3: Cross multiply
   11,321.57x = 15,638.73 × 9,439.31
4. Step 4: Simplify right side
   11,321.57x = 147,618,820.48
5. Step 5: Solve for x
   x = 147,618,820.48/11,321.57
6. Step 6: Final answer
   x = 13,038.72