Finding the Fourth Proportional to 2,215.83, 3,317.31 and 1,288.56

Step by Step Solution

1. Step 1: Write the proportion equation
   2,215.83 : 3,317.31 = 1,288.56 : x
2. Step 2: Convert to fraction form
   2,215.83/3,317.31 = 1,288.56/x
3. Step 3: Cross multiply
   2,215.83x = 3,317.31 × 1,288.56
4. Step 4: Simplify right side
   2,215.83x = 4,274,552.97
5. Step 5: Solve for x
   x = 4,274,552.97/2,215.83
6. Step 6: Final answer
   x = 1,929.10