Finding the Fourth Proportional to 2,215.65, 3,057.61 and 1,220.96

Step by Step Solution

1. Step 1: Write the proportion equation
   2,215.65 : 3,057.61 = 1,220.96 : x
2. Step 2: Convert to fraction form
   2,215.65/3,057.61 = 1,220.96/x
3. Step 3: Cross multiply
   2,215.65x = 3,057.61 × 1,220.96
4. Step 4: Simplify right side
   2,215.65x = 3,733,227.67
5. Step 5: Solve for x
   x = 3,733,227.67/2,215.65
6. Step 6: Final answer
   x = 1,684.94