Parallel and Intersecting Lines

A set of vocabulary flashcards based on the Grade 7 lecture notes regarding geometric properties of intersecting, parallel, and perpendicular lines.

Intersecting Lines

Lines that meet each other at a point on a plane surface.

Linear Pairs

Adjacent angles formed by two lines intersecting each other that always add up to $180^{\circ}$.

Vertically Opposite Angles

Opposite angles formed by two lines intersecting each other that are always equal to each other.

Proof

A mathematical justification of a reasoning, such as the conclusion that vertically opposite angles are equal.

Perpendicular Lines

A pair of lines which intersect each other at right angles ($90^{\circ}$).

Parallel Lines

A pair of lines that lie on the same plane and do not meet however far they are extended at both ends.

Notation for Parallel Lines

In mathematics, an arrow mark ($>$) used to show that a set of lines is parallel.

Transversal

A line that intersects two or more different lines, forming eight angles.

Corresponding Angles

Angles that correspond to each other based on their position when a transversal intersects two different lines.

Alternate Angles

Angles formed by a transversal intersecting a pair of parallel lines that are always equal to each other.

Interior Angles (on the same side)

Angles formed by a transversal intersecting a pair of parallel lines that always add up to $180^{\circ}$.