Finding the Fourth Proportional to 2,255.16, 3,379.86 and 1,215.57

Step by Step Solution

1. Step 1: Write the proportion equation
   2,255.16 : 3,379.86 = 1,215.57 : x
2. Step 2: Convert to fraction form
   2,255.16/3,379.86 = 1,215.57/x
3. Step 3: Cross multiply
   2,255.16x = 3,379.86 × 1,215.57
4. Step 4: Simplify right side
   2,255.16x = 4,108,456.42
5. Step 5: Solve for x
   x = 4,108,456.42/2,255.16
6. Step 6: Final answer
   x = 1,821.80