Finding the Fourth Proportional to 2,216.45, 3,058.77 and 1,221.80

Step by Step Solution

1. Step 1: Write the proportion equation
   2,216.45 : 3,058.77 = 1,221.80 : x
2. Step 2: Convert to fraction form
   2,216.45/3,058.77 = 1,221.80/x
3. Step 3: Cross multiply
   2,216.45x = 3,058.77 × 1,221.80
4. Step 4: Simplify right side
   2,216.45x = 3,737,189.89
5. Step 5: Solve for x
   x = 3,737,189.89/2,216.45
6. Step 6: Final answer
   x = 1,686.12