Finding the Fourth Proportional to 255.50, 381.42 and 216.72

Step by Step Solution

1. Step 1: Write the proportion equation
   255.50 : 381.42 = 216.72 : x
2. Step 2: Convert to fraction form
   255.50/381.42 = 216.72/x
3. Step 3: Cross multiply
   255.50x = 381.42 × 216.72
4. Step 4: Simplify right side
   255.50x = 82,661.34
5. Step 5: Solve for x
   x = 82,661.34/255.50
6. Step 6: Final answer
   x = 323.53