Finding the Fourth Proportional to 91.89, 137.25 and 79.74

Step by Step Solution

1. Step 1: Write the proportion equation
   91.89 : 137.25 = 79.74 : x
2. Step 2: Convert to fraction form
   91.89/137.25 = 79.74/x
3. Step 3: Cross multiply
   91.89x = 137.25 × 79.74
4. Step 4: Simplify right side
   91.89x = 10,944.32
5. Step 5: Solve for x
   x = 10,944.32/91.89
6. Step 6: Final answer
   x = 119.10