Finding the Fourth Proportional to 2,215.76, 3,057.59 and 1,220.83

Step by Step Solution

1. Step 1: Write the proportion equation
   2,215.76 : 3,057.59 = 1,220.83 : x
2. Step 2: Convert to fraction form
   2,215.76/3,057.59 = 1,220.83/x
3. Step 3: Cross multiply
   2,215.76x = 3,057.59 × 1,220.83
4. Step 4: Simplify right side
   2,215.76x = 3,732,793.01
5. Step 5: Solve for x
   x = 3,732,793.01/2,215.76
6. Step 6: Final answer
   x = 1,684.66