Finding the Fourth Proportional to 2,105.07, 2,905.01 and 1,221.40

Step by Step Solution

1. Step 1: Write the proportion equation
   2,105.07 : 2,905.01 = 1,221.40 : x
2. Step 2: Convert to fraction form
   2,105.07/2,905.01 = 1,221.40/x
3. Step 3: Cross multiply
   2,105.07x = 2,905.01 × 1,221.40
4. Step 4: Simplify right side
   2,105.07x = 3,548,158.58
5. Step 5: Solve for x
   x = 3,548,158.58/2,105.07
6. Step 6: Final answer
   x = 1,685.53