Finding the Fourth Proportional to 2,103.30, 3,156.15 and 805.70

Step by Step Solution

1. Step 1: Write the proportion equation
   2,103.30 : 3,156.15 = 805.70 : x
2. Step 2: Convert to fraction form
   2,103.30/3,156.15 = 805.70/x
3. Step 3: Cross multiply
   2,103.30x = 3,156.15 × 805.70
4. Step 4: Simplify right side
   2,103.30x = 2,542,910.06
5. Step 5: Solve for x
   x = 2,542,910.06/2,103.30
6. Step 6: Final answer
   x = 1,209.01