Finding the Fourth Proportional to 1,391.40, 1,920.23 and 801.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,391.40 : 1,920.23 = 801.98 : x
2. Step 2: Convert to fraction form
   1,391.40/1,920.23 = 801.98/x
3. Step 3: Cross multiply
   1,391.40x = 1,920.23 × 801.98
4. Step 4: Simplify right side
   1,391.40x = 1,539,974.45
5. Step 5: Solve for x
   x = 1,539,974.45/1,391.40
6. Step 6: Final answer
   x = 1,106.78