Finding the Fourth Proportional to 1,392.72, 1,921.91 and 803.13

Step by Step Solution

1. Step 1: Write the proportion equation
   1,392.72 : 1,921.91 = 803.13 : x
2. Step 2: Convert to fraction form
   1,392.72/1,921.91 = 803.13/x
3. Step 3: Cross multiply
   1,392.72x = 1,921.91 × 803.13
4. Step 4: Simplify right side
   1,392.72x = 1,543,539.56
5. Step 5: Solve for x
   x = 1,543,539.56/1,392.72
6. Step 6: Final answer
   x = 1,108.29