Finding the Fourth Proportional to 2,105.10, 2,904.80 and 1,220.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,105.10 : 2,904.80 = 1,220.72 : x
2. Step 2: Convert to fraction form
   2,105.10/2,904.80 = 1,220.72/x
3. Step 3: Cross multiply
   2,105.10x = 2,904.80 × 1,220.72
4. Step 4: Simplify right side
   2,105.10x = 3,545,947.46
5. Step 5: Solve for x
   x = 3,545,947.46/2,105.10
6. Step 6: Final answer
   x = 1,684.46