Finding the Fourth Proportional to 2,105.04, 2,905.23 and 1,221.12

Step by Step Solution

1. Step 1: Write the proportion equation
   2,105.04 : 2,905.23 = 1,221.12 : x
2. Step 2: Convert to fraction form
   2,105.04/2,905.23 = 1,221.12/x
3. Step 3: Cross multiply
   2,105.04x = 2,905.23 × 1,221.12
4. Step 4: Simplify right side
   2,105.04x = 3,547,634.46
5. Step 5: Solve for x
   x = 3,547,634.46/2,105.04
6. Step 6: Final answer
   x = 1,685.31