Finding the Fourth Proportional to 128.76, 192.72 and 106

Step by Step Solution

1. Step 1: Write the proportion equation
   128.76 : 192.72 = 106 : x
2. Step 2: Convert to fraction form
   128.76/192.72 = 106/x
3. Step 3: Cross multiply
   128.76x = 192.72 × 106
4. Step 4: Simplify right side
   128.76x = 20,428.32
5. Step 5: Solve for x
   x = 20,428.32/128.76
6. Step 6: Final answer
   x = 158.65