Finding the Fourth Proportional to 1,391.69, 1,920.51 and 802.23

Step by Step Solution

1. Step 1: Write the proportion equation
   1,391.69 : 1,920.51 = 802.23 : x
2. Step 2: Convert to fraction form
   1,391.69/1,920.51 = 802.23/x
3. Step 3: Cross multiply
   1,391.69x = 1,920.51 × 802.23
4. Step 4: Simplify right side
   1,391.69x = 1,540,690.74
5. Step 5: Solve for x
   x = 1,540,690.74/1,391.69
6. Step 6: Final answer
   x = 1,107.07