Finding the Fourth Proportional to 13,136.76, 18,131.76 and 8,661.30

Step by Step Solution

1. Step 1: Write the proportion equation
   13,136.76 : 18,131.76 = 8,661.30 : x
2. Step 2: Convert to fraction form
   13,136.76/18,131.76 = 8,661.30/x
3. Step 3: Cross multiply
   13,136.76x = 18,131.76 × 8,661.30
4. Step 4: Simplify right side
   13,136.76x = 157,044,612.89
5. Step 5: Solve for x
   x = 157,044,612.89/13,136.76
6. Step 6: Final answer
   x = 11,954.59