Finding the Fourth Proportional to 13,128.78, 18,117.36 and 7,160.16

Step by Step Solution

1. Step 1: Write the proportion equation
   13,128.78 : 18,117.36 = 7,160.16 : x
2. Step 2: Convert to fraction form
   13,128.78/18,117.36 = 7,160.16/x
3. Step 3: Cross multiply
   13,128.78x = 18,117.36 × 7,160.16
4. Step 4: Simplify right side
   13,128.78x = 129,723,196.38
5. Step 5: Solve for x
   x = 129,723,196.38/13,128.78
6. Step 6: Final answer
   x = 9,880.83