Finding the Fourth Proportional to 2,105.92, 2,905.92 and 1,221.76

Step by Step Solution

1. Step 1: Write the proportion equation
   2,105.92 : 2,905.92 = 1,221.76 : x
2. Step 2: Convert to fraction form
   2,105.92/2,905.92 = 1,221.76/x
3. Step 3: Cross multiply
   2,105.92x = 2,905.92 × 1,221.76
4. Step 4: Simplify right side
   2,105.92x = 3,550,336.82
5. Step 5: Solve for x
   x = 3,550,336.82/2,105.92
6. Step 6: Final answer
   x = 1,685.88