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SAT questions. Answers D,C,C,D. Section 4.1 – Classifying Triangles. November 11, 2009. Triangle defined. 3 sided polygon POLYGON defined: a closed figure in a plane that is made up of segments, called sides that intersect only at their endpoints, called vertices.
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SAT questions • Answers D,C,C,D
Section 4.1 – Classifying Triangles November 11, 2009
Triangle defined • 3 sided polygon • POLYGON defined: a closed figure in a plane that is made up of segments, called sides that intersect only at their endpoints, called vertices.
Triangles are named by: Sides and Angles. • SIDES • Scalene – no sides are congruent • Isosceles – 2 sides are congruent • Equilateral – 3 sides are congruent
Triangles are names by Sides and Angles: • ANGLES • Acute – all 3 angles are acute • Obtuse – one angle is obtuse • Right – one angle is 90º • Equiangular – all angles are equal (60º)
Parts of Triangles • Isosceles Triangles: • Legs – 2 congruent sides • Base – side opposite the vertex < • Vertex < - angle formed by the legs • Base <s – 2 angles opposite the legs VERTEX ANGLE LEG LEG BASE ANGLE BASE ANGLE BASE
Parts of an Isosceles Triangle • Side Opposite <EDF : FE • Angle Opposite DE : <F
Parts of a Right Triangle • Hypotenuse: side opposite the right angle • Legs: two sides adjacent to the right angle ACUTE ANGLES LEG HYPOTENUSE RIGHT ANGLE LEG
Labeling a Triangle A. List sides - List angles - B. C. Side and angles opposite each other – <A <B <C
HOMEWORK: PRACTICE WORKBOOK 4 – 1 #1-10 * You may use a classroom protractor for #8 & 9 if you don’t have one. Return it at the end of class.