Finding the Fourth Proportional to 1,019.72, 1,405.20 and 724.48

Step by Step Solution

1. Step 1: Write the proportion equation
   1,019.72 : 1,405.20 = 724.48 : x
2. Step 2: Convert to fraction form
   1,019.72/1,405.20 = 724.48/x
3. Step 3: Cross multiply
   1,019.72x = 1,405.20 × 724.48
4. Step 4: Simplify right side
   1,019.72x = 1,018,032.27
5. Step 5: Solve for x
   x = 1,018,032.27/1,019.72
6. Step 6: Final answer
   x = 998.34