Triangles

1
5-3
Triangles
Warm Up
Lesson Presentation
Pre-Algebra
2

• Warm Up
• Solve each equation.
• 62 x 37 180
• 2. x 90 11 180

x 81
x 79
3
Learn to find unknown angles in triangles.
Triangle Sum Theorem
The three angles of any triangle, in the plane,
can be added up to equal 180.
4
Find the measure of angle p.
73 44 p 180
117 p 180
P 63
5
Match the term describing a triangle with the
correct definition.
B
A. One angle equal to 90 B. 3 angles less than
90 C. One angle greater than 90
____ Acute ____ Right ____ Obtuse
A
C
6
Find c, then classify the triangle.
42 90 c 180
132 c 180
c 48
Right
7
Find m, then classify the triangle.
23 62 m 180
85 m 180
m 95
Obtuse
8
Find a, then classify the triangle.
88 38 a 180
38
126 a 180
a 54
Acute
88
a
9
Find b, then classify the triangle.
38 90 b 180
128 b 180
38
b 52
Right
b
10
Find c, then classify the triangle.
24 38 c 180
62 c 180
c 118
38
Obtuse
24
c
11
Lesson Quiz Part 1
1. Find the missing angle measure in the acute
triangle shown.
38
12
Lesson Quiz Part 2
2. Find the missing angle measure in an obtuse
triangle with angle measures of 10 and 15.
155
13
Homework

• Pg 236
• 1 3, 7 10, 15 20, 39 41