Finding the Fourth Proportional to 2,103.12, 3,156.09 and 870.51

Step by Step Solution

1. Step 1: Write the proportion equation
   2,103.12 : 3,156.09 = 870.51 : x
2. Step 2: Convert to fraction form
   2,103.12/3,156.09 = 870.51/x
3. Step 3: Cross multiply
   2,103.12x = 3,156.09 × 870.51
4. Step 4: Simplify right side
   2,103.12x = 2,747,407.91
5. Step 5: Solve for x
   x = 2,747,407.91/2,103.12
6. Step 6: Final answer
   x = 1,306.35