Finding the Fourth Proportional to 2,106.45, 2,906.78 and 1,222.11

Step by Step Solution

1. Step 1: Write the proportion equation
   2,106.45 : 2,906.78 = 1,222.11 : x
2. Step 2: Convert to fraction form
   2,106.45/2,906.78 = 1,222.11/x
3. Step 3: Cross multiply
   2,106.45x = 2,906.78 × 1,222.11
4. Step 4: Simplify right side
   2,106.45x = 3,552,398.80
5. Step 5: Solve for x
   x = 3,552,398.80/2,106.45
6. Step 6: Final answer
   x = 1,686.44