Finding the Fourth Proportional to 1,392.12, 1,921.10 and 802.68

Step by Step Solution

1. Step 1: Write the proportion equation
   1,392.12 : 1,921.10 = 802.68 : x
2. Step 2: Convert to fraction form
   1,392.12/1,921.10 = 802.68/x
3. Step 3: Cross multiply
   1,392.12x = 1,921.10 × 802.68
4. Step 4: Simplify right side
   1,392.12x = 1,542,028.55
5. Step 5: Solve for x
   x = 1,542,028.55/1,392.12
6. Step 6: Final answer
   x = 1,107.68