Finding the Fourth Proportional to 122.72, 169.56 and 100.88

Step by Step Solution

1. Step 1: Write the proportion equation
   122.72 : 169.56 = 100.88 : x
2. Step 2: Convert to fraction form
   122.72/169.56 = 100.88/x
3. Step 3: Cross multiply
   122.72x = 169.56 × 100.88
4. Step 4: Simplify right side
   122.72x = 17,105.21
5. Step 5: Solve for x
   x = 17,105.21/122.72
6. Step 6: Final answer
   x = 139.38