1. Unit 1 Angles formed by parallel lines. Standards MCC8G1-5

2. The angles created when Parallel Lines Are Cut By A Transversal: Alternate Interior Angles (congruent) Alternate Exterior Angles (congruent) Corresponding Angles (congruent) Vertical Angles (congruent) Consecutive Interior Angles (sum to 180°) Supplementary Angles (sum to 180°)

3. Similar Triangles If two triangles have two congruent angle measures, then the triangles are similar. 45° 50°

4. Exterior Angles of a Triangle An exterior angle of a triangle is formed by any side of a triangle and the extension of its adjacent side. The Exterior Angle Theorem states that An exterior angle of a triangle is equal to the sum of the two opposite interior angles.

5. Adapted from the Arizona Department of Education Show that m ∠ 3 + m ∠ 4 + m ∠ 5 = 180˚, given that lines l and m are parallel lines and t 1 & t 2 are transversals. Find the m ∠ a, m ∠ b, and the m ∠ c if line n and segment yz are parallel. n

6. If lines m, n and p are parallel and cut by transversals t and s, find the measures of angles 1 and 2. m n p 67° 23° 1 2 t s

7. Examples & Explanations If lines m, n and p are parallel and cut by transversals t and s, find the measures of angles 1 and 2. m n p 67° 23° 1 2 t s

8. Examples & Explanations If lines m, n and p are parallel and cut by transversals t and s, find the measures of angles 1 and 2. m n p 67° 23° 1 2 t s

9. Examples & Explanations If lines m, n and p are parallel and cut by transversals t and s, find the measures of angles 1 and 2. m n p 67° 23° 1 2 t s

10. Examples & Explanations If lines m, n and p are parallel and cut by transversals t and s, find the measures of angles 1 and 2. m n p 67° 23° 1 2 t s

11. Examples & Explanations If lines m, n and p are parallel and cut by transversals t and s, find the measures of angles 1 and 2. m n p 67° 23° 1 2 t s

12. Examples & Explanations If lines m, n and p are parallel and cut by transversals t and s, find the measures of angles 1 and 2. m n p 67° 23° 67° t s