Finding the Fourth Proportional to 2,105.59, 2,905.86 and 1,221.49

Step by Step Solution

1. Step 1: Write the proportion equation
   2,105.59 : 2,905.86 = 1,221.49 : x
2. Step 2: Convert to fraction form
   2,105.59/2,905.86 = 1,221.49/x
3. Step 3: Cross multiply
   2,105.59x = 2,905.86 × 1,221.49
4. Step 4: Simplify right side
   2,105.59x = 3,549,478.93
5. Step 5: Solve for x
   x = 3,549,478.93/2,105.59
6. Step 6: Final answer
   x = 1,685.74