Finding the Fourth Proportional to 12,691.57, 17,516.21 and 7,389.31

Step by Step Solution

1. Step 1: Write the proportion equation
   12,691.57 : 17,516.21 = 7,389.31 : x
2. Step 2: Convert to fraction form
   12,691.57/17,516.21 = 7,389.31/x
3. Step 3: Cross multiply
   12,691.57x = 17,516.21 × 7,389.31
4. Step 4: Simplify right side
   12,691.57x = 129,432,705.72
5. Step 5: Solve for x
   x = 129,432,705.72/12,691.57
6. Step 6: Final answer
   x = 10,198.32