Finding the Fourth Proportional to 321.18, 443.22 and 279.72

Step by Step Solution

1. Step 1: Write the proportion equation
   321.18 : 443.22 = 279.72 : x
2. Step 2: Convert to fraction form
   321.18/443.22 = 279.72/x
3. Step 3: Cross multiply
   321.18x = 443.22 × 279.72
4. Step 4: Simplify right side
   321.18x = 123,978.02
5. Step 5: Solve for x
   x = 123,978.02/321.18
6. Step 6: Final answer
   x = 386.01