Finding the Fourth Proportional to 91.50, 137.25 and 79.89

Step by Step Solution

1. Step 1: Write the proportion equation
   91.50 : 137.25 = 79.89 : x
2. Step 2: Convert to fraction form
   91.50/137.25 = 79.89/x
3. Step 3: Cross multiply
   91.50x = 137.25 × 79.89
4. Step 4: Simplify right side
   91.50x = 10,964.90
5. Step 5: Solve for x
   x = 10,964.90/91.50
6. Step 6: Final answer
   x = 119.84