Finding the Fourth Proportional to 1,391.76, 1,920.63 and 802.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,391.76 : 1,920.63 = 802.30 : x
2. Step 2: Convert to fraction form
   1,391.76/1,920.63 = 802.30/x
3. Step 3: Cross multiply
   1,391.76x = 1,920.63 × 802.30
4. Step 4: Simplify right side
   1,391.76x = 1,540,921.45
5. Step 5: Solve for x
   x = 1,540,921.45/1,391.76
6. Step 6: Final answer
   x = 1,107.17