Finding the Fourth Proportional to 1,392.57, 1,921.59 and 803.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,392.57 : 1,921.59 = 803.30 : x
2. Step 2: Convert to fraction form
   1,392.57/1,921.59 = 803.30/x
3. Step 3: Cross multiply
   1,392.57x = 1,921.59 × 803.30
4. Step 4: Simplify right side
   1,392.57x = 1,543,603.64
5. Step 5: Solve for x
   x = 1,543,603.64/1,392.57
6. Step 6: Final answer
   x = 1,108.46