Finding the Fourth Proportional to 8,640.69, 12,960.83 and 4,479.32

Step by Step Solution

1. Step 1: Write the proportion equation
   8,640.69 : 12,960.83 = 4,479.32 : x
2. Step 2: Convert to fraction form
   8,640.69/12,960.83 = 4,479.32/x
3. Step 3: Cross multiply
   8,640.69x = 12,960.83 × 4,479.32
4. Step 4: Simplify right side
   8,640.69x = 58,055,617.83
5. Step 5: Solve for x
   x = 58,055,617.83/8,640.69
6. Step 6: Final answer
   x = 6,718.86