Finding the Fourth Proportional to 2,216.57, 3,058.67 and 1,221.60

Step by Step Solution

1. Step 1: Write the proportion equation
   2,216.57 : 3,058.67 = 1,221.60 : x
2. Step 2: Convert to fraction form
   2,216.57/3,058.67 = 1,221.60/x
3. Step 3: Cross multiply
   2,216.57x = 3,058.67 × 1,221.60
4. Step 4: Simplify right side
   2,216.57x = 3,736,471.27
5. Step 5: Solve for x
   x = 3,736,471.27/2,216.57
6. Step 6: Final answer
   x = 1,685.70