Finding the Fourth Proportional to 2,156.23, 3,229.48 and 1,288.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,156.23 : 3,229.48 = 1,288.72 : x
2. Step 2: Convert to fraction form
   2,156.23/3,229.48 = 1,288.72/x
3. Step 3: Cross multiply
   2,156.23x = 3,229.48 × 1,288.72
4. Step 4: Simplify right side
   2,156.23x = 4,161,872.87
5. Step 5: Solve for x
   x = 4,161,872.87/2,156.23
6. Step 6: Final answer
   x = 1,930.17