Finding the Fourth Proportional to 12,786.66, 17,645.85 and 7,121.52

Step by Step Solution

1. Step 1: Write the proportion equation
   12,786.66 : 17,645.85 = 7,121.52 : x
2. Step 2: Convert to fraction form
   12,786.66/17,645.85 = 7,121.52/x
3. Step 3: Cross multiply
   12,786.66x = 17,645.85 × 7,121.52
4. Step 4: Simplify right side
   12,786.66x = 125,665,273.69
5. Step 5: Solve for x
   x = 125,665,273.69/12,786.66
6. Step 6: Final answer
   x = 9,827.84