Finding the Fourth Proportional to 13,136.50, 18,128.31 and 7,168.15

Step by Step Solution

1. Step 1: Write the proportion equation
   13,136.50 : 18,128.31 = 7,168.15 : x
2. Step 2: Convert to fraction form
   13,136.50/18,128.31 = 7,168.15/x
3. Step 3: Cross multiply
   13,136.50x = 18,128.31 × 7,168.15
4. Step 4: Simplify right side
   13,136.50x = 129,946,373.13
5. Step 5: Solve for x
   x = 129,946,373.13/13,136.50
6. Step 6: Final answer
   x = 9,892.01