Finding the Fourth Proportional to 2,320.17, 3,480.27 and 858.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,320.17 : 3,480.27 = 858.72 : x
2. Step 2: Convert to fraction form
   2,320.17/3,480.27 = 858.72/x
3. Step 3: Cross multiply
   2,320.17x = 3,480.27 × 858.72
4. Step 4: Simplify right side
   2,320.17x = 2,988,577.45
5. Step 5: Solve for x
   x = 2,988,577.45/2,320.17
6. Step 6: Final answer
   x = 1,288.09