Finding the Fourth Proportional to 2,156.88, 3,236.16 and 858.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,156.88 : 3,236.16 = 858.72 : x
2. Step 2: Convert to fraction form
   2,156.88/3,236.16 = 858.72/x
3. Step 3: Cross multiply
   2,156.88x = 3,236.16 × 858.72
4. Step 4: Simplify right side
   2,156.88x = 2,778,955.32
5. Step 5: Solve for x
   x = 2,778,955.32/2,156.88
6. Step 6: Final answer
   x = 1,288.41