Finding the Fourth Proportional to 13,128.64, 18,117.72 and 7,160.29

Step by Step Solution

1. Step 1: Write the proportion equation
   13,128.64 : 18,117.72 = 7,160.29 : x
2. Step 2: Convert to fraction form
   13,128.64/18,117.72 = 7,160.29/x
3. Step 3: Cross multiply
   13,128.64x = 18,117.72 × 7,160.29
4. Step 4: Simplify right side
   13,128.64x = 129,728,084.04
5. Step 5: Solve for x
   x = 129,728,084.04/13,128.64
6. Step 6: Final answer
   x = 9,881.31