Finding the Fourth Proportional to 2,320.24, 3,480.20 and 858.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,320.24 : 3,480.20 = 858.72 : x
2. Step 2: Convert to fraction form
   2,320.24/3,480.20 = 858.72/x
3. Step 3: Cross multiply
   2,320.24x = 3,480.20 × 858.72
4. Step 4: Simplify right side
   2,320.24x = 2,988,517.34
5. Step 5: Solve for x
   x = 2,988,517.34/2,320.24
6. Step 6: Final answer
   x = 1,288.02