Finding the Fourth Proportional to 2,456.40, 3,684.86 and 812.30

Step by Step Solution

1. Step 1: Write the proportion equation
   2,456.40 : 3,684.86 = 812.30 : x
2. Step 2: Convert to fraction form
   2,456.40/3,684.86 = 812.30/x
3. Step 3: Cross multiply
   2,456.40x = 3,684.86 × 812.30
4. Step 4: Simplify right side
   2,456.40x = 2,993,211.78
5. Step 5: Solve for x
   x = 2,993,211.78/2,456.40
6. Step 6: Final answer
   x = 1,218.54