Finding the Fourth Proportional to 13,097.15, 18,074.12 and 7,128.79

Step by Step Solution

1. Step 1: Write the proportion equation
   13,097.15 : 18,074.12 = 7,128.79 : x
2. Step 2: Convert to fraction form
   13,097.15/18,074.12 = 7,128.79/x
3. Step 3: Cross multiply
   13,097.15x = 18,074.12 × 7,128.79
4. Step 4: Simplify right side
   13,097.15x = 128,846,525.09
5. Step 5: Solve for x
   x = 128,846,525.09/13,097.15
6. Step 6: Final answer
   x = 9,837.76