Finding the Fourth Proportional to 1,392.32, 1,921.60 and 803.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,392.32 : 1,921.60 = 803.20 : x
2. Step 2: Convert to fraction form
   1,392.32/1,921.60 = 803.20/x
3. Step 3: Cross multiply
   1,392.32x = 1,921.60 × 803.20
4. Step 4: Simplify right side
   1,392.32x = 1,543,429.12
5. Step 5: Solve for x
   x = 1,543,429.12/1,392.32
6. Step 6: Final answer
   x = 1,108.53