Finding the Fourth Proportional to 321.72, 482.55 and 105.31

Step by Step Solution

1. Step 1: Write the proportion equation
   321.72 : 482.55 = 105.31 : x
2. Step 2: Convert to fraction form
   321.72/482.55 = 105.31/x
3. Step 3: Cross multiply
   321.72x = 482.55 × 105.31
4. Step 4: Simplify right side
   321.72x = 50,817.34
5. Step 5: Solve for x
   x = 50,817.34/321.72
6. Step 6: Final answer
   x = 157.96