8.15 Parallel Lines and Polygons

Parallel Lines and Polygons

1. 1. Identify alternate, corresponding and co-interior angles formed by a transversal crossing parallel lines.
2. 2. Calculate unknown angles in parallel-line diagrams.
3. 3. Apply the triangle angle sum theorem to determine unknown angles.
4. 4. Calculate the sum of the interior angles of a polygon using (n − 2) × 180°.
5. 5. Calculate the size of one interior angle of a regular polygon.
6. 6. Use the fact that exterior angles of a polygon sum to 360°.
7. 7. Solve algebraic angle problems where angles in parallel-line or polygon diagrams are given as expressions in x.