Question

1. give a counter example to the statement below.

if two lines intersect, then they intersect at a 90 - degree angle.

Explanation:

A counterexample needs two intersecting lines that do not form a 90-degree angle. For instance, two lines crossing at 45 degrees satisfy intersection but not perpendicularity, disproving the statement.

Answer:

Two lines intersecting at a 45-degree angle (or any non-90-degree angle, e.g., 30 degrees).