Finding the Fourth Proportional to 1,392.72, 1,921.78 and 803.24

Step by Step Solution

1. Step 1: Write the proportion equation
   1,392.72 : 1,921.78 = 803.24 : x
2. Step 2: Convert to fraction form
   1,392.72/1,921.78 = 803.24/x
3. Step 3: Cross multiply
   1,392.72x = 1,921.78 × 803.24
4. Step 4: Simplify right side
   1,392.72x = 1,543,650.57
5. Step 5: Solve for x
   x = 1,543,650.57/1,392.72
6. Step 6: Final answer
   x = 1,108.37