Download Gr8_Unit 4 Math Parent Connection

Partners for Student Success
Eighth Grade Mathematics
Unit 4: Geometry: Stability & Change
In order for your child to be successful, it is important to be consistent with the mathematical
vocabulary and processes that will be implemented this year in eighth grade. You may find this
resource helpful when supporting your child at home.
Unit Concepts
Concept
Explanation
Alternate exterior
angles
Angles that are on the
outside of a pair of lines
and on opposite sides of
the transversal
Alternate interior
angles
Angles that are in the
inside of a pair of lines
and on opposite sides of
the transversal
Congruent
Same size and same
shape. Congruent
polygons have angles that
are the same measure,
shapes that are the same,
and side lengths that are
proportional.
Converse
Switching the hypothesis
& conclusion in a
statement
Corresponding
angles
Angles that lie on the
same side of the
transversal and in
corresponding positions
Cecil County Public Schools
2014 – 2015
Examples
and
are congruent because they are the
same shape, same size and the corresponding (matching)
angles have the same measure.
Statement: If a figure is a triangle, then it is a polygon.
Converse: If a figure is a polygon, then it is a triangle.
NOTE: The converse is not necessarily true.
1
Grade 8
Unit 4 Partners for Student Success
Concept
Explanation
Exterior angle
The exterior angle is the
angle between any side of
a shape, and a line
extended from the next
side
Image
A figure or polygon after
a transformation or series
of transformations was
performed
Pre-image
Parallel lines
Pythagorean
Theorem
Similar
Square roots
A figure or polygon
before a transformation
or series of
transformations was
performed (the original
figure)
Lines are parallel if they
lie in the same plane, and
are the same distance
apart over their entire
length. They will never
intersect
The relationship of side
lengths in a right triangle,
a and b
represent the length of
the hypotenuse
Similar polygons have
angles that are the same
measure, shapes, that are
the same, and side
lengths that are
proportional
Examples
(pre-image) was transformed by performing a
rotation and dilation to get
(image).
was
rotated
and dilated with a scale factor of 2.
and
are similar because they are the same
shape, the corresponding (matching) angles have the
same measure, and the sides are proportional; all sides on
are 2 times the length of the corresponding sides
on
One of two equal factors
of a number
Cecil County Public Schools
2014 – 2015
2
Grade 8
Unit 4 Partners for Student Success
Concept
Explanation
Examples
Transformation
Manipulating a figure by
translations, rotations,
reflections, and/or
dilations
Translation- sliding a figure
Rotation- turning a figure
Reflection- making a mirror image
Dilation- enlarging or reducing a figure
Transversal
A line or line segment
that intersects two or
more (often parallel)
lines or line segments
Volume of a sphere =
The capacity of a 3D
figure, how many cubic
units it can hold
Volume
4 3
pr
3
Volume of a cylinder = p r 2 h
Volume of a cone =
1 2
pr h
3
Additional Resources

www.corestandards.org
o View the math standards your child will be learning this year. Scroll down and click
“Mathematics Standards” to download the pdf document.

www.ixl.com/math/standards/common-core
o Click “Eighth Grade” to find interactive practice opportunities aligned with each
math standard.

www.studyjams.com
o Using the search bar, find interactive examples and opportunities for practice for any
given concept.

www.khanacademy.org
o Using the search bar, find videos and examples on several math concepts throughout
the year

http://www.ccps.org/math/Parent%20Materials/Middle/parent_mid.html
o
Process guides are provided for concepts covered in each unit. Check back often, as
this site will be updated throughout the year.
Cecil County Public Schools
2014 – 2015
3
Grade 8
Unit 4 Partners for Student Success