Finding the Fourth Proportional to 1,390.88, 1,919.42 and 801.41

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.88 : 1,919.42 = 801.41 : x
2. Step 2: Convert to fraction form
   1,390.88/1,919.42 = 801.41/x
3. Step 3: Cross multiply
   1,390.88x = 1,919.42 × 801.41
4. Step 4: Simplify right side
   1,390.88x = 1,538,228.78
5. Step 5: Solve for x
   x = 1,538,228.78/1,390.88
6. Step 6: Final answer
   x = 1,105.94