Finding the Fourth Proportional to 443.29, 664.82 and 211.72

Step by Step Solution

1. Step 1: Write the proportion equation
   443.29 : 664.82 = 211.72 : x
2. Step 2: Convert to fraction form
   443.29/664.82 = 211.72/x
3. Step 3: Cross multiply
   443.29x = 664.82 × 211.72
4. Step 4: Simplify right side
   443.29x = 140,755.69
5. Step 5: Solve for x
   x = 140,755.69/443.29
6. Step 6: Final answer
   x = 317.53