- Topics At a Glance
- Basic Shapes & Angles
- Angles
**Parallel Lines & Transversals**- Polygons
- Triangles
- Quadrilaterals
- Angles in a Polygon
- Circles
- Similar Figures
- Perimeter & Circumference
- Area (Polygon, Triangle, Circle, Square)
- Area Formulas
- Area of Irregular Shapes
- 3D Objects (Prisms, Cylinders, Cones, Spheres)
- Volume of Prisms & Cylinders
- Volume of Pyramids & Cones
- Volume of Spheres
- Surface Area
- Pythagorean Theorem

A transversal is a line that intersects two or more other lines. When it intersects parallel lines, many angles are congruent. Let's take a peek at what this means. Lines *k* and *j* are parallel. Line *l *is a transversal.

As we mentioned before, when this happens we get a bunch of pairs of congruent angles. These pairs have nifty vocabulary terms to go with them. Here they are:

- Corresponding angles - angles that are in the same position on each line. There are four sets of these angles: .
- Alternate interior angles - angles on the opposite sides of the transversal and on the interior of the parallel lines. There are two sets of alternate interior angles: .
- Alternate exterior angles - angles on opposite sides of the transversal and on the exterior of the parallel lines. There are two sets of alternate exterior angles: .

*Look Out**: these pairs of angles are congruent only when the transversal cuts parallel lines.*

Example 1

Lines . |

Refer to this diagram for Exercises 1-4

Lines *m, n*, and *o* are parallel.

Exercise 1

What angles are corresponding to ?

Exercise 2

What is the measure of ?

Exercise 3

Which angles have measurements of 75°?

Exercise 4

Which angles have measures of 105°?