classification of triangles. table of contents objective objective review review definition of a...
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Table of ContentsTable of ContentsObjective
Review
Definition of a Triangle
Samples of Triangular Objects
Types of angles
Congruence of Line Segments
According to Angle Measure
According to Length of sides
Review Questions
Objective:Objective:
At the end of the lesson, At the end of the lesson, the students should be the students should be able to classify triangles.able to classify triangles.
Acute AngleAcute Angle-It is an angle whose measure -It is an angle whose measure
is less than 90is less than 9000..
300
AA
BB
CC
<BAC which <BAC which is an acute is an acute angle.angle.
Right Angle-It is an angle whose -It is an angle whose
measure is equal to 90measure is equal to 9000..
900
Obtuse Angle- It is an angle whose - It is an angle whose
measure is greater than measure is greater than 909000 but less than 180 but less than 18000..
1500
*Two segments are congruent if and only if they have
equal length.C D
10 cm
10 cm
measure of AB = measure of CD
A B
CLASSIFICATION OF TRIANGLES
According to anglesAccording to angles
According to sidesAccording to sides
600 48O
*ACUTE TRIANGLE*ACUTE TRIANGLE-All the angles of the -All the angles of the
triangle are acute.triangle are acute.
J LJ L
KK
720 <J,<K,<L are all acute angles.
RIGHT TRIANGLERIGHT TRIANGLE-An angle in a triangle -An angle in a triangle
is a right angle.is a right angle.
909000
M OM O
NN
<M is a right angle.
leg
leg
The side opposite the right angle of a right triangle is called the hypotenuse. The other sides are called legs.
HYPOTENUSE
OBTUSE TRIANGLEOBTUSE TRIANGLE- An angle in a triangle is an obtuse - An angle in a triangle is an obtuse
angle.angle.
PP
1281280 0
<P is an <P is an obtuse angle.obtuse angle.
RR
SCALENE TRIANGLESCALENE TRIANGLE
--No two sides are congruent.No two sides are congruent.
AA
BB
AAB B == BCBC == CACA
4 cm
6 cm
CC9 cm
~~~~
D FD F
ISOSCELES TRIANGLEISOSCELES TRIANGLE--two sides of the are congruent.two sides of the are congruent.
EE
DE = FEDE = FE
basebase
legleg legleg
The two equal sides of an isosceles triangle are called legs. The third side is called the base.
~~
EQUILATERAL EQUILATERAL TRIANGLETRIANGLE
--Three sides are congruent.Three sides are congruent.
G IG I
HH
GH = HI = GIGH = HI = GI~~ ~~