Finding the Fourth Proportional to 388.56, 582.72 and 258.72

Step by Step Solution

1. Step 1: Write the proportion equation
   388.56 : 582.72 = 258.72 : x
2. Step 2: Convert to fraction form
   388.56/582.72 = 258.72/x
3. Step 3: Cross multiply
   388.56x = 582.72 × 258.72
4. Step 4: Simplify right side
   388.56x = 150,761.32
5. Step 5: Solve for x
   x = 150,761.32/388.56
6. Step 6: Final answer
   x = 388.00