Finding the Fourth Proportional to 2,103.78, 3,155.84 and 870.96

Step by Step Solution

1. Step 1: Write the proportion equation
   2,103.78 : 3,155.84 = 870.96 : x
2. Step 2: Convert to fraction form
   2,103.78/3,155.84 = 870.96/x
3. Step 3: Cross multiply
   2,103.78x = 3,155.84 × 870.96
4. Step 4: Simplify right side
   2,103.78x = 2,748,590.27
5. Step 5: Solve for x
   x = 2,748,590.27/2,103.78
6. Step 6: Final answer
   x = 1,306.50