Geometry
Name ______________________
Period ___________
Date ___________
Intro to Triangles Day 1
Triangle Sum Classwork
1. Classify Each Triangle by its sides and angle measures.
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Plot the given points and connect them to make a triangle. Find the lengths and slopes of each side of the
triangle. Then classify these triangles using two names.
2. A(0, 0) B(-1, 2) C(6, 3)
3. D(0, 0) E(2, 3) F(4, 0)
In the following triangles, Use the Triangles Sum Theorem or the Exterior Angles Theorem to solve for the
missing variables.
4.
5.
80o
42o
xo
60o
xo
6.
7.
(4x-5)
8.
xo
o
(3x+11)
yo
o
8.
9.
2y
10.
o
50o
The variable expressions represent the angle measures of a triangle. Find the measures of each
angle. Then classify the triangle by full name.
11.
12.
mA ( x  30 )o
m B  x o
mC ( x  60 )o
mA (6 x  11 )o
mB (3x  2 )o
mC ( 5x  1 )o