Finding the Fourth Proportional to 91.38, 136.71 and 89.49

Step by Step Solution

1. Step 1: Write the proportion equation
   91.38 : 136.71 = 89.49 : x
2. Step 2: Convert to fraction form
   91.38/136.71 = 89.49/x
3. Step 3: Cross multiply
   91.38x = 136.71 × 89.49
4. Step 4: Simplify right side
   91.38x = 12,234.18
5. Step 5: Solve for x
   x = 12,234.18/91.38
6. Step 6: Final answer
   x = 133.88