Finding the Fourth Proportional to 2,572.34, 3,859.20 and 840.96

Step by Step Solution

1. Step 1: Write the proportion equation
   2,572.34 : 3,859.20 = 840.96 : x
2. Step 2: Convert to fraction form
   2,572.34/3,859.20 = 840.96/x
3. Step 3: Cross multiply
   2,572.34x = 3,859.20 × 840.96
4. Step 4: Simplify right side
   2,572.34x = 3,245,432.83
5. Step 5: Solve for x
   x = 3,245,432.83/2,572.34
6. Step 6: Final answer
   x = 1,261.67