1. 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.

2. 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

3. 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

4. Triangles!! Angles formed by Perpendicular Lines - CKC p. 612 1 m
CKC p. 61
Triangles!!
Scalene Triangle -
No congruent sides
Isosceles Triangle -
At least 2 congruent sides
Equilateral Triangle -
3 congruent sides

5. 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

6. Ex 2 – are equiangular. FindC S A R K Y T

7. Out – what 2 ways can you classify triangles?
Summary – Today, I think…
HW – p. 71 #1-9