Finding the Fourth Proportional to 2,426.65, 3,640.05 and 671.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,426.65 : 3,640.05 = 671.78 : x
2. Step 2: Convert to fraction form
   2,426.65/3,640.05 = 671.78/x
3. Step 3: Cross multiply
   2,426.65x = 3,640.05 × 671.78
4. Step 4: Simplify right side
   2,426.65x = 2,445,321.89
5. Step 5: Solve for x
   x = 2,445,321.89/2,426.65
6. Step 6: Final answer
   x = 1,007.70