Finding the Fourth Proportional to 2,010.78, 3,017.25 and 840.60

Step by Step Solution

1. Step 1: Write the proportion equation
   2,010.78 : 3,017.25 = 840.60 : x
2. Step 2: Convert to fraction form
   2,010.78/3,017.25 = 840.60/x
3. Step 3: Cross multiply
   2,010.78x = 3,017.25 × 840.60
4. Step 4: Simplify right side
   2,010.78x = 2,536,300.35
5. Step 5: Solve for x
   x = 2,536,300.35/2,010.78
6. Step 6: Final answer
   x = 1,261.35