Theorems Of Perpendicular Lines

Theorem 3.4: If two sides of adjacent acute angles are perpendicular, then the angles are complementary.

Theorem 3.3: If two lines intersect to form adjacent congruent angles ,then the lines are perpendicular.

Theorem 3.2: If two lines are perpendicular, then they intersect to form 4 right angles.

Theorem 3.1: All right angles are congruent. 

Perpendicual , Parallel , and Skew Lines

Today I learned about parallel ,perpendicular and skew lines. I learned that lines that parallel lines are lines that lie in the same plane and do not intersect. Perpendicular lines are lines that intersect to form an right angle. Skew lines are lines that do not lie in the same plane and don't intersect . Parallel lines and skew lines are similar because they both don't intersect, but the difference is parallel lines lie in the same plane while skew lines don't. Also skew lines and parallel lines are different from perpendicular lines because they don't intersect ,while perpendicular lines are.