Classifying Triangles

1
Classifying Triangles
Shanon.V. Marty.R. Vilma.V.
2
Standard 12.0

• Students find and use measures of sides and of
  interior and exterior angles of triangles and
  polygons to classify figures and solve problems.
  

3
Classify By Angles

• An Acute triangle
• - it has 3 acute angles
• A Right triangle
• - it has 1 right angle
• A Obtuse Triangle
• - it has 1 obtuse angle
• A Equiangular Triangle
• -three congruent acute
  angles

4
Classify By Sides

• Equilateral Triangle
• - 3 congruent sides
• Isosceles Triangle
• - at least 2 congruent sides
• Scalene Triangle
• - no sides are equal

5
Classifying Triangles by Angles Measures

• EHG
• EHG is a right angle. So
• EHG is a right triangle.
• EFH
• EFH and HFG form a linear
• pair, so they are supplementary. Therefore
• mltEFH mltHFG 180?. By substitution,
• mltEFH 60? 180?. So mltEFH 120?. EFH is an
  obtuse triangle by definition.

H
30?
30?
60?
60?
E
F
G
6
Classifying Triangles by Side Lengths

• ABC
• From the Figure, AB AC. So AC 15, and
  ABC is equilateral.
• ABC
• By the Segment Addition Postulate,
• BD BC CD 15 5 20. Since no
• sides are congruent, ABD is scalene.

A
18
15
D
B
C
15
5
7
CLASSWORK HOMEWORK

• CLASSWORK GREENBOOK PG. 219 1-10
• HOMEWORK GREENBOOK PG. 220 23-28