MJ2 - Ch 10.5 Quadrilaterals
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Transcript MJ2 - Ch 10.5 Quadrilaterals
MJ2
Ch 10.5 - Quadrilaterals
Bellwork
Draw the triangles and find the value
of x
1.
2.
x°
34°
56°
53°
x°
Assignment Review
Reminder:
Your Triangle Poster is Due on _________
I will add 5 points to your grade if your
poster is handed in on ___________
Unfortunately, If the poster is not handed in
by ________ I will give you a zero (0) as I
do not accept late assignments!
Before we begin…
Please take out your notebook and
get ready to work…
For the past couple of days we have
been studying angles and triangles…
Today we will look at quadrilaterals…
Raise your hand if you know what a
quadrilateral is…
Quadrilaterals
Correct…a quadrilateral is a closed
figure with 4 sides and 4 angles…
Raise your hand if you can name
some examples…
Objective
Students will classify and find the
missing angle measure of
quadrilaterals.
Classifying Quadrilaterals
When classifying quadrilaterals you
use the name that best describes it…
That means we all need to have the
same understanding of the
characteristics of each type of
quadrilateral
Please copy the vocabulary on the
next slide…
Vocabulary
Quadrilateral – any 4 sided, 4 angle figure
Trapezoid – a quadrilateral with one pair
of parallel sides
Parallelogram – a quadrilateral with
opposite sides parallel and opposite sides
congruent
Rectangle – a parallelogram with 4 right
angles
Square – a parallelogram with 4 right
angles and 4 congruent sides
Rhombus – a parallelogram with 4
congruent sides
Comments
When viewing pictures of quadrilaterals
there are 2 types symbols that you need to
be aware of
The hash mark (/) means the sides are
congruent. If multiple sides are congruent
you will see 1 or 2 hash marks
The arrow () indicates that the sides are
parallel. If multiple sides are parallel you
will see 1 or 2 arrows.
Lets look at some examples…
Examples
Square: 4 right angles & 4
congruent sides
Trapezoid – 1 set of parallel
sides
Missing Angle Measurements
All the angles in any quadrilateral
equal 360° .
To find the missing measure use the
same process as finding the angles of
a triangle.
1. Add up the given angles and subtract
from 360° .
2. Lets look at an example…
Example
Before you begin…look
at angle x.
Will it be >90°, <90°,
or =90° ? Why?
Raise your hand if you
know the answer..
108°
55°
x°
59°
Example
Correct…because x is an
obtuse angle it will be
greater than 90°
The reason you look at
that is to make sure that
your answer is
reasonable…so if you get
an answer less than or
equal to 90°, you have to
question it!
108°
55°
x°
59°
Example
To find the missing measure
add up the angles and
55°
subtract from 360°.
360-(108+55+59)=x
360 – 222 = x
138 = x
Therefore, x = 138°
and your answer is reasonable!
108°
x°
59°
Your Turn
In the notes section of your notebook
draw the figure and solve for x
x°
113°
Summary
In the notes section of your notebook
summarize the key concepts covered
in today’s lesson
Today we discussed
The types of quadrilaterals – you will see
this on a test!
How to find the missing angle of a
quadrilateral!
Assignment
Quadrilateral Concept Map
Follow the directions on the sheet!