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

In geometry, a transversal is a line that passes through two lines in the same
plane at two ... Further, if the **angles** of one pair are **congruent**, then the **angles** of
each of the other pairs are also ... This contradicts Proposition 16 which states
that an exterior **angle** of a triangle is **always** greater than the opposite interior
**angles**.

socratic.org/questions/what-types-of-angles-are-always-congruent

Jul 28, 2016 **...** Right **angles** ( 90o ) Straight **angles** ( 180o ) Complete **angles** ( 360o ) See below
...

www.mathopenref.com/anglesvertical.html

As can be seen from the figure above, when two lines intersect, four **angles** are
formed. Each opposite pair are called vertical **angles** and are **always congruent**.

www.mathopenref.com/congruentangles.html

**Angles** are **congruent** if they have the same **angle** measure in degrees. They can
be at any orientation on the plane. In the figure above, there are two **congruent** ...

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.khanacademy.org/math/geometry-home/geometry-angles/geometry-vert-comp-supp/v/proof-vertical-angles-are-equal

Proving that vertical **angles** are equal. ... Vertical **angles** are **congruent** proof ......
**angle** DBA-- then I'd prove that vertical **angles** are **always** going to be equal, ...

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.varsitytutors.com/hotmath/hotmath_help/topics/vertical-angles-theorem

Vertical **Angles** Theorem. Theorem:Vertical **angles** are **always congruent**. In the
figure, ∠1≅∠3 and ∠2≅∠4. Proof: ∠1and∠2 form a linear pair, so by the ...