2.1/2.2 Angles and Triangles Warm-up (IN) Learning Objective: to identify and classify angles and triangles, to estimate and calculate measures of angles Warm-up (IN) A D R W 20º 70º 55º Use the diagram: Name 2 congruent segments. Name 2 congruent angles. Name 2 perpendicular segments. Name 2 complementary angles. Name 2 supplementary angles. Name an obtuse angle. Name a right angle. Name an acute angle.
Notes Adjacent Angles - Coplanar angles that share a vertex and a side but don’t overlap 1 2 Linear Pair - 2 adjacent angles whose non-shared angles form a straight angle. 1 2 Linear Pair Property - Angles in a linear pair are supplementary
Non-adjacent, non-overlapping angles formed by intersecting lines Vertical Angles - Non-adjacent, non-overlapping angles formed by intersecting lines 1 2 Vertical Angles Property - Vertical angles are congruent! Ex 1 – Find the value of each variable. Name the property that you used. c=50º Linear pair property 130º cº dº d=50º Vertical angles property
Triangles!! Angles formed by Perpendicular Lines - CKC p. 61 2 1 m CKC p. 61 Triangles!! Scalene Triangle - No congruent sides Isosceles Triangle - At least 2 congruent sides Equilateral Triangle - 3 congruent sides
The sum of the angles in a triangle = 3 acute angles Acute Triangle - Obtuse Triangle - 1 obtuse angle Right Triangle - 1 right angle Triangle Sum Theorem - The sum of the angles in a triangle = 180º 1 2 3 A C B
Ex 2 – are equiangular. Find C S A R K Y T
Out – what 2 ways can you classify triangles? Summary – Today, I think… HW – p. 71 #1-9