Download Notes 4B: Triangle Angle Measures Vocabulary

Notes 4B: Triangle Angle Measures
Vocabulary:
When the sides of a triangle are extended, the angles
that are adjacent to the interior angles are exterior angles.
<d, <e, <f are the
exterior angles of the
triangle
e
d
f
Theorem 4.2 Exterior Angle Theorem
The measure of an exterior angle of a triangle
is equal to the sum of the measures of the two
nonadjacent interior angles.
e
d=a+b
e=b+c
f=a+c
a
b
c d
f
Corallary to the Triangle Sum Theroem
The acute angles of a right triangle are complimentary.
a+b+c=180o
b
90o +b+c=180o
b+c=90o
a
c
Find the value of the missing angles.
1.
2.
x
x
y
53 o
y
60o
3.
y
68o
x 102o
Theorem 4.6 Base Angle Theorem
If two sides of a triangle are congruent then the angles
opposite the sides are congruent.
Theorem 4.7 Converse of The Base Angle Theorem
If two angles of a triangle are congruent, then the sides
opposite them are congruent.
Thm. 4.6
Thm. 4.7
a
a
If
Then...
If
Then...
<b = <c
b
c
b
c
ab=ac
9Use
the information provided in the drawing to find x and y.
1.
y
2.
50o
y
26o
x
x
*3.
*4.
x
o
140
95o
x
y
y
Finding missing angles in Triangles with Vertical and Linear Pairs:
*Linear Pair:______________________
4
1
3
2
Vertical Angles:______________________
Use the information provided in the drawing to find x and/or y.
1.
2.
Finding missing angles with Equilateral Triangles:
Equilaterial:______________________
3
Equiangular:______________________
2
1
Use the information provided in the drawing to find x and/or y.
1.
2.
Let's practice! Find x and y:
3.
4.
5.
xo
yo
Assignment:
Worksheet 4B