Finding the Fourth Proportional to 2,166.42, 2,989.74 and 1,222.17

Step by Step Solution

1. Step 1: Write the proportion equation
   2,166.42 : 2,989.74 = 1,222.17 : x
2. Step 2: Convert to fraction form
   2,166.42/2,989.74 = 1,222.17/x
3. Step 3: Cross multiply
   2,166.42x = 2,989.74 × 1,222.17
4. Step 4: Simplify right side
   2,166.42x = 3,653,970.54
5. Step 5: Solve for x
   x = 3,653,970.54/2,166.42
6. Step 6: Final answer
   x = 1,686.64