Finding the Fourth Proportional to 91.33, 136.89 and 39.89

Step by Step Solution

1. Step 1: Write the proportion equation
   91.33 : 136.89 = 39.89 : x
2. Step 2: Convert to fraction form
   91.33/136.89 = 39.89/x
3. Step 3: Cross multiply
   91.33x = 136.89 × 39.89
4. Step 4: Simplify right side
   91.33x = 5,460.88
5. Step 5: Solve for x
   x = 5,460.88/91.33
6. Step 6: Final answer
   x = 59.79