Finding the Fourth Proportional to 13,108.72, 18,087.72 and 7,731.40

Step by Step Solution

1. Step 1: Write the proportion equation
   13,108.72 : 18,087.72 = 7,731.40 : x
2. Step 2: Convert to fraction form
   13,108.72/18,087.72 = 7,731.40/x
3. Step 3: Cross multiply
   13,108.72x = 18,087.72 × 7,731.40
4. Step 4: Simplify right side
   13,108.72x = 139,843,398.41
5. Step 5: Solve for x
   x = 139,843,398.41/13,108.72
6. Step 6: Final answer
   x = 10,667.97