Finding the Fourth Proportional to 2,859.12, 3,945.72 and 2,159.28

Step by Step Solution

1. Step 1: Write the proportion equation
   2,859.12 : 3,945.72 = 2,159.28 : x
2. Step 2: Convert to fraction form
   2,859.12/3,945.72 = 2,159.28/x
3. Step 3: Cross multiply
   2,859.12x = 3,945.72 × 2,159.28
4. Step 4: Simplify right side
   2,859.12x = 8,519,914.28
5. Step 5: Solve for x
   x = 8,519,914.28/2,859.12
6. Step 6: Final answer
   x = 2,979.91