en.wikipedia.org/wiki/Transversal_(geometry)

In geometry, a transversal is a line that passes through two lines in the same
plane at two ... types of pairs of angles: consecutive interior angles,
corresponding angles, ... If the two angles of ...

study.com/academy/lesson/types-of-angles-vertical-corresponding-alternate-interior-others.html

They are defined as a pair of nonadjacent angles formed by only two intersecting
lines. They are known as 'Kissing Vs' and always have congruent measures.

www.answers.com/Q/Which_types_of_angles_are_always_congruent

vertical angles are always congruent...they are two nonadjacent angles formed
by intersecting lines. Vertical angles are congruent..or equal in measure.

www.mathopenref.com/anglesvertical.html

Definition and properties of vertical (or opposite) angles. ... Each opposite pair
are called vertical angles and are always congruent. The red ... Angle Types.

www.regentsprep.org/regents/math/geometry/gp5/langles.htm

www.mathplanet.com/education/pre-algebra/introducing-geometry/angles-and-parallel-lines

Vertical angles are always congruent, which means that they are equal. Adjacent
angles are angles that come out of the same vertex. Adjacent angles share a ...

www.mathsisfun.com/geometry/congruent-angles.html

Congruent Angles have the same angle (in degrees or radians). That is all. ... the
same angle. Congruent - why such a funny word that basically means "equal"?

www.mathsisfun.com/geometry/corresponding-angles.html

Corresponding Angles. When two lines are crossed by another line (called the
Transversal):. The angles in matching corners are called Corresponding Angles.

www.reference.com/math/corresponding-angles-3672ba39fdbca955

These corresponding angles are equal or congruent if the... ... Some other types
of angles formed are adjacent angles, consecutive interior angles, alternate ...

www.math10.com/en/geometry/angles/angles.html

Angles between two parallel lines that are cut by a third line. ... Recall that all
pairs of vertical angles are congruent. Supplementary pairs: angle 1 and angle 2