Finding the Fourth Proportional to 1,392.15, 1,921.59 and 803.07

Step by Step Solution

1. Step 1: Write the proportion equation
   1,392.15 : 1,921.59 = 803.07 : x
2. Step 2: Convert to fraction form
   1,392.15/1,921.59 = 803.07/x
3. Step 3: Cross multiply
   1,392.15x = 1,921.59 × 803.07
4. Step 4: Simplify right side
   1,392.15x = 1,543,171.28
5. Step 5: Solve for x
   x = 1,543,171.28/1,392.15
6. Step 6: Final answer
   x = 1,108.48