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Lesson 7-4: Triangles
p. 262 – 271
1. A _______________ is a plane figure that consists of line segments
joining three or more points. Each line segment is a ________ of the
polygon and the endpoints of each side are called ______________.
2. When three points that are not all on the same line are joined in pairs
by line segments, the figure formed is a ______________.
3. An ____________ triangle as three acute angles.
4. An _______________ triangle has three angles equal in measure.
5. A _____________ triangle has one right angle.
6. An _____________ triangle has one obtuse angle.
7. The sum of the measures of the angles of a triangle is ____________.
8. An ______________ triangle has three sides equal in length.
9. An ______________ triangle has two sides equal in length.
10. A ______________ triangle has no sides equal in length.
TERM
Acute Triangle
Equiangular Triangle
EXAMPLE
Right Triangle
Obtuse Triangle
Scalene Triangle
Isosceles Triangle
Equilateral Triangle
Ex1| Classify the following triangles by their angles.
a)
b)
c)
d)
Ex2| Find the measure of the third angle of a triangle if the measures of
the two angles are 72.6o and 84.2o.
Ex3| In ABC , the measure of B is twice the measure of A , and the
measure of C is 3 times the measure of A . Find the number of degrees
in each angle of the triangle.
A =
B =
C =
A + B + C = ______
Ex4| Classify the following triangles by their sides.
a)
b)
HW: p. 267/3-33 3’s
c)