Finding the Fourth Proportional to 755.59, 1,131.72 and 390.73

Step by Step Solution

1. Step 1: Write the proportion equation
   755.59 : 1,131.72 = 390.73 : x
2. Step 2: Convert to fraction form
   755.59/1,131.72 = 390.73/x
3. Step 3: Cross multiply
   755.59x = 1,131.72 × 390.73
4. Step 4: Simplify right side
   755.59x = 442,196.96
5. Step 5: Solve for x
   x = 442,196.96/755.59
6. Step 6: Final answer
   x = 585.23