Finding the Fourth Proportional to 443.50, 665.50 and 215.50

Step by Step Solution

1. Step 1: Write the proportion equation
   443.50 : 665.50 = 215.50 : x
2. Step 2: Convert to fraction form
   443.50/665.50 = 215.50/x
3. Step 3: Cross multiply
   443.50x = 665.50 × 215.50
4. Step 4: Simplify right side
   443.50x = 143,415.25
5. Step 5: Solve for x
   x = 143,415.25/443.50
6. Step 6: Final answer
   x = 323.37