Finding the Fourth Proportional to 443.31, 664.72 and 212.05

Step by Step Solution

1. Step 1: Write the proportion equation
   443.31 : 664.72 = 212.05 : x
2. Step 2: Convert to fraction form
   443.31/664.72 = 212.05/x
3. Step 3: Cross multiply
   443.31x = 664.72 × 212.05
4. Step 4: Simplify right side
   443.31x = 140,955.37
5. Step 5: Solve for x
   x = 140,955.37/443.31
6. Step 6: Final answer
   x = 317.96