Finding the Fourth Proportional to 128.96, 177.72 and 96.15

Step by Step Solution

1. Step 1: Write the proportion equation
   128.96 : 177.72 = 96.15 : x
2. Step 2: Convert to fraction form
   128.96/177.72 = 96.15/x
3. Step 3: Cross multiply
   128.96x = 177.72 × 96.15
4. Step 4: Simplify right side
   128.96x = 17,087.78
5. Step 5: Solve for x
   x = 17,087.78/128.96
6. Step 6: Final answer
   x = 132.51