Finding the Fourth Proportional to 1,640.57, 2,462.25 and 818.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,640.57 : 2,462.25 = 818.60 : x
2. Step 2: Convert to fraction form
   1,640.57/2,462.25 = 818.60/x
3. Step 3: Cross multiply
   1,640.57x = 2,462.25 × 818.60
4. Step 4: Simplify right side
   1,640.57x = 2,015,597.85
5. Step 5: Solve for x
   x = 2,015,597.85/1,640.57
6. Step 6: Final answer
   x = 1,228.60