Finding the Fourth Proportional to 1,391.41, 1,919.61 and 801.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,391.41 : 1,919.61 = 801.91 : x
2. Step 2: Convert to fraction form
   1,391.41/1,919.61 = 801.91/x
3. Step 3: Cross multiply
   1,391.41x = 1,919.61 × 801.91
4. Step 4: Simplify right side
   1,391.41x = 1,539,354.46
5. Step 5: Solve for x
   x = 1,539,354.46/1,391.41
6. Step 6: Final answer
   x = 1,106.33