Finding the Fourth Proportional to 1,057.78, 1,585.86 and 480.25

Step by Step Solution

1. Step 1: Write the proportion equation
   1,057.78 : 1,585.86 = 480.25 : x
2. Step 2: Convert to fraction form
   1,057.78/1,585.86 = 480.25/x
3. Step 3: Cross multiply
   1,057.78x = 1,585.86 × 480.25
4. Step 4: Simplify right side
   1,057.78x = 761,609.27
5. Step 5: Solve for x
   x = 761,609.27/1,057.78
6. Step 6: Final answer
   x = 720.01