Finding the Fourth Proportional to 1,392.13, 1,921.08 and 802.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,392.13 : 1,921.08 = 802.72 : x
2. Step 2: Convert to fraction form
   1,392.13/1,921.08 = 802.72/x
3. Step 3: Cross multiply
   1,392.13x = 1,921.08 × 802.72
4. Step 4: Simplify right side
   1,392.13x = 1,542,089.34
5. Step 5: Solve for x
   x = 1,542,089.34/1,392.13
6. Step 6: Final answer
   x = 1,107.72