Section 1.5
Lesson 6
August 2
Triangles, and special quadrilaterals
Warm ups Lesson
6
Use for #4 and 5
Use for #1 and 2
A
B
1


F  G  C
D
E
1. Name 1 two other ways
S T I
N K
4. TN ∩ IK
5. ST  TI
2. FGA & ____ are
vertical angles.
3. Two angles are complementary. The measure of one
angles is 12x -4 and the measure of the other angles is
8x + 14. Find the measure of the smaller angle. Show
work.
Right Triangle
Classify Differentiate Test
A right triangle is a TRIANGLE that HAS ONE RIGHT ANGLE
75º
50
º
60
º
40
º
60
º
45
º
45
º
Right
Triangles
15
º
60
º
85
50º
45
ºNot º
Right Triangles
Acute Triangle
Differentiate Test
Classify
An Acute triangle is a TRIANGLE that HAS 3 ACUTE ANGLES
50°
3 7°
40°
28°
51°
132°
80°
63°
72°
66°
21°
40°
55°
85°
Acute Triangles
Not
Acute Triangles
Obtuse Triangle
Classify Differentiate Test
An Obtuse triangle is a TRIANGLE that HAS 1 OBTUSE ANGLE
40°
50°
55°
21°
85°
40°
112°
3 7°
47°
132°
21°
Obtuse Triangles
Not
Obtuse Triangles
Scalene Triangle
Classify Differentiate Test
A Scalene triangle is a TRIANGLE that has no congruent sides
6
5
7
11
5
17 17
8
Scalene Triangles
9
12
Not 17
Scalene Triangles
6
8
Equilateral Triangle
Classify Differentiate Test
A Equilateral triangle is a TRIANGLE that has three congruent sides
17
9
9
8
9
Equilateral Triangles
Not
equilateral Triangles
9
Isosceles Triangle
Classify Differentiate Test
An Isosceles triangle is a TRIANGLE that has at least 2 congruent sides
17
17 17
2
Isosceles Triangles
8
Not
Isosceles Triangles
9
Quadrilaterals- a polygon that has 4 sides is called a quadrilateral.
Quadrilaterals
Parallelogram
_______________ __________________
Square
_____________
Any polygon with
A parallelogram With
4 right angles and 4
congruent sides
4 sides
Trapezoid
____________
Only 1 pair of
parallel sides
Opposite sides are
congruent and parallel
Rectangle
______________
a parallelogram
with 4 right angles
Rhombus
______________
A parallelogram with
4 congruent sides
Quadrilaterals (book definitions)
• A trapezoid is a quadrilateral with exactly one pair
of parallel sides.
• A kite is a quadrilateral with two distinct pairs of
consecutive congruent sides.
• A parallelogram is a quadrilateral with two pairs of
parallel sides.
• A rhombus is an equilateral parallelogram.
• A rectangle is a parallelogram with four congruent
angles.
• A square is a parallelogram with four congruent
sides and angles.
What can you assume?
K
I
E
F
T
E
G
H
A quadrilateral with Kite TKIE A quadrilateral with Parallelogram
two congruent sides
2 right angles
HGEF
and one right angle
Identify the figure
Isosceles Obtuse triangle
Right Triangle
Rhombus
Isosceles right triangle
Right
Trapezoid
Triangle
Kite
Rectangle
Parallelogram
Parallelogram
Trapezoid
Kite
Isosceles Obtuse triangle Rhombus and
Parallelogram
Isosceles
Rectangle and
right triangle
Parallelogram
Sketch and label the figure. Mark the
figure
C
Isosceles acute triangle ACT with AC = CT
E
Kite TEKI with TE = EK
T
K
T
A
T
Rhombus LEFT with diagonal LF and
I ET
intersecting at I
L
I
F
Draw a octagon with exactly 2 outside diagonals
E
Homework
• Complete Lesson 7
Quadrilaterals handout- a polygon that has 4 sides is called a quadrilateral.
_______________ __________________
_____________
Any polygon with
A parallelogram With
4 right angles and 4
congruent sides
4 sides
____________
Only 1 pair of
parallel sides
Opposite sides are
congruent and parallel
______________
a parallelogram
with 4 right angles
______________
A parallelogram with
4 congruent sides