Finding the Fourth Proportional to 128.33, 191.72 and 89.49

Step by Step Solution

1. Step 1: Write the proportion equation
   128.33 : 191.72 = 89.49 : x
2. Step 2: Convert to fraction form
   128.33/191.72 = 89.49/x
3. Step 3: Cross multiply
   128.33x = 191.72 × 89.49
4. Step 4: Simplify right side
   128.33x = 17,156.38
5. Step 5: Solve for x
   x = 17,156.38/128.33
6. Step 6: Final answer
   x = 133.69