Finding the Fourth Proportional to 2,920.42, 4,380.55 and 840.43

Step by Step Solution

1. Step 1: Write the proportion equation
   2,920.42 : 4,380.55 = 840.43 : x
2. Step 2: Convert to fraction form
   2,920.42/4,380.55 = 840.43/x
3. Step 3: Cross multiply
   2,920.42x = 4,380.55 × 840.43
4. Step 4: Simplify right side
   2,920.42x = 3,681,545.64
5. Step 5: Solve for x
   x = 3,681,545.64/2,920.42
6. Step 6: Final answer
   x = 1,260.62