Finding the Fourth Proportional to 2,456.64, 3,686.40 and 918.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,456.64 : 3,686.40 = 918.72 : x
2. Step 2: Convert to fraction form
   2,456.64/3,686.40 = 918.72/x
3. Step 3: Cross multiply
   2,456.64x = 3,686.40 × 918.72
4. Step 4: Simplify right side
   2,456.64x = 3,386,769.41
5. Step 5: Solve for x
   x = 3,386,769.41/2,456.64
6. Step 6: Final answer
   x = 1,378.62