Finding the Fourth Proportional to 1,057.92, 1,587.42 and 480.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,057.92 : 1,587.42 = 480.72 : x
2. Step 2: Convert to fraction form
   1,057.92/1,587.42 = 480.72/x
3. Step 3: Cross multiply
   1,057.92x = 1,587.42 × 480.72
4. Step 4: Simplify right side
   1,057.92x = 763,104.54
5. Step 5: Solve for x
   x = 763,104.54/1,057.92
6. Step 6: Final answer
   x = 721.33