Finding the Fourth Proportional to 1,370.89, 1,891.81 and 781.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,370.89 : 1,891.81 = 781.42 : x
2. Step 2: Convert to fraction form
   1,370.89/1,891.81 = 781.42/x
3. Step 3: Cross multiply
   1,370.89x = 1,891.81 × 781.42
4. Step 4: Simplify right side
   1,370.89x = 1,478,298.17
5. Step 5: Solve for x
   x = 1,478,298.17/1,370.89
6. Step 6: Final answer
   x = 1,078.35