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NAME _____________________________________________ DATE ____________________________ PERIOD _____________
Section 4-1
Classifying Triangles
Classify each triangle as acute, equiangular, obtuse, or right.
1.
2.
3.
Classify each triangle as scalene, isosceles, or equilateral.
4.△ABD
5. △ABC
6. △EDC
7. △BDC
ALGEBRA For each triangle, find x and the measure of each side.
8. △FGH is an equilateral triangle with FG = x + 5, GH = 3x – 9, and FH = 2x – 2.
9. △LMN is an isosceles triangle, with LM =LN, LM = 3x – 2, LN =2x + 1, and MN = 5x – 2.
LOOKING AHEAD: Using the internet, research the Triangle Sum Theorem and the Exterior Angle Theorem.
10. Triangle Sum Theorem: ________________________________________________________________________
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11. Exterior Angle Theorem: _______________________________________________________________________
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NAME _____________________________________________ DATE ____________________________ PERIOD _____________
Anticipation Guide
Agree, Disagree,
or Unsure
WHAT DO YOU KNOW?
Agree, Disagree,
or Unsure
The following could be the angle measures
of an acute triangle. 30o, 80o, 70o.
An obtuse triangle is a triangle with three
obtuse angles.
The term “equilangular” denotes a triangle
with three 50o angles.
A scalene triangle has two equal sides.
Side lengths that measure 3 in, 3 in and 5in
will form an isosceles triangle.
A right triangle is a triangle with one 90o
angle.
The sum of the interior angles of a triangle
is always 180o.
Chapter 4
6
Glencoe Geometry