Finding the Fourth Proportional to 2,103.59, 3,155.76 and 870.31

Step by Step Solution

1. Step 1: Write the proportion equation
   2,103.59 : 3,155.76 = 870.31 : x
2. Step 2: Convert to fraction form
   2,103.59/3,155.76 = 870.31/x
3. Step 3: Cross multiply
   2,103.59x = 3,155.76 × 870.31
4. Step 4: Simplify right side
   2,103.59x = 2,746,489.49
5. Step 5: Solve for x
   x = 2,746,489.49/2,103.59
6. Step 6: Final answer
   x = 1,305.62