# What is the difference between alternate and corresponding angles?

##### 1 Answer

See the picture and explanation below.

#### Explanation:

When two *parallel* lines are intersected by the third (*transversal*), they form eight angles: one of the parallel lines forms four angles

Two acute angles *transversal*, lying on the same side from a *transversal*, are called *corresponding*.

So are other pairs (acute and obtuse) similarly positioned:

One of corresponding angles is always *interior* (in between parallel lines) and another - *exterior* (outside of the area in between parallel lines).

Two acute angles *transversal*, lying on the opposite sides from a *transversal*, are called *alternate*.

So are other pairs (acute and obtuse) similarly positioned:

The alternate angles are either both *interior* or both *exterior*.

The classical theorem of geometry states that *corresponding* angles are congruent. The same for *alternate interior* and *alternate exterior* angles.