Finding the Fourth Proportional to 1,340.89, 1,850.51 and 781.40

Step by Step Solution

1. Step 1: Write the proportion equation
   1,340.89 : 1,850.51 = 781.40 : x
2. Step 2: Convert to fraction form
   1,340.89/1,850.51 = 781.40/x
3. Step 3: Cross multiply
   1,340.89x = 1,850.51 × 781.40
4. Step 4: Simplify right side
   1,340.89x = 1,445,995.09
5. Step 5: Solve for x
   x = 1,445,995.09/1,340.89
6. Step 6: Final answer
   x = 1,078.39