Finding the Fourth Proportional to 105.72, 146.22 and 100.32

Step by Step Solution

1. Step 1: Write the proportion equation
   105.72 : 146.22 = 100.32 : x
2. Step 2: Convert to fraction form
   105.72/146.22 = 100.32/x
3. Step 3: Cross multiply
   105.72x = 146.22 × 100.32
4. Step 4: Simplify right side
   105.72x = 14,668.79
5. Step 5: Solve for x
   x = 14,668.79/105.72
6. Step 6: Final answer
   x = 138.75