Finding the Fourth Proportional to 8,659.39, 12,979.83 and 3,111.20

Step by Step Solution

1. Step 1: Write the proportion equation
   8,659.39 : 12,979.83 = 3,111.20 : x
2. Step 2: Convert to fraction form
   8,659.39/12,979.83 = 3,111.20/x
3. Step 3: Cross multiply
   8,659.39x = 12,979.83 × 3,111.20
4. Step 4: Simplify right side
   8,659.39x = 40,382,847.10
5. Step 5: Solve for x
   x = 40,382,847.10/8,659.39
6. Step 6: Final answer
   x = 4,663.47