Angle Between Two Lines

Step 1: Concept
Check the product of the slopes . If it equals -1, the lines are perpendicular.
Step 2: Analysis
and . .
Step 3: Conclusion
Since the product of slopes is -1, the angle between the lines is .
Final Answer: (C)

Concept: Angle between two lines with slopes and :

Step 1: Identify slopes.


Step 2: Compute numerator.


Step 3: Compute denominator.


Step 4: Find angle.