Finding the Fourth Proportional to 12,686.76, 17,507.70 and 7,381.89

Step by Step Solution

1. Step 1: Write the proportion equation
   12,686.76 : 17,507.70 = 7,381.89 : x
2. Step 2: Convert to fraction form
   12,686.76/17,507.70 = 7,381.89/x
3. Step 3: Cross multiply
   12,686.76x = 17,507.70 × 7,381.89
4. Step 4: Simplify right side
   12,686.76x = 129,239,915.55
5. Step 5: Solve for x
   x = 129,239,915.55/12,686.76
6. Step 6: Final answer
   x = 10,186.99