Finding the Fourth Proportional to 1,391.17, 1,920.23 and 802.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,391.17 : 1,920.23 = 802.12 : x
2. Step 2: Convert to fraction form
   1,391.17/1,920.23 = 802.12/x
3. Step 3: Cross multiply
   1,391.17x = 1,920.23 × 802.12
4. Step 4: Simplify right side
   1,391.17x = 1,540,254.89
5. Step 5: Solve for x
   x = 1,540,254.89/1,391.17
6. Step 6: Final answer
   x = 1,107.17