Finding the Fourth Proportional to 1,392.56, 1,921.70 and 803.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,392.56 : 1,921.70 = 803.42 : x
2. Step 2: Convert to fraction form
   1,392.56/1,921.70 = 803.42/x
3. Step 3: Cross multiply
   1,392.56x = 1,921.70 × 803.42
4. Step 4: Simplify right side
   1,392.56x = 1,543,932.21
5. Step 5: Solve for x
   x = 1,543,932.21/1,392.56
6. Step 6: Final answer
   x = 1,108.70