Download Angle and Regular Polygon Review

Line Symmetry / Reflection Symmetry Review
Questions
Draw a square and draw all lines of symmetry on this 2-d
shape.
What kinds of lines of symmetry does the square have?
Now draw a triangle that has all interior angles the same
size and all sides the same size.
What kinds of lines of symmetry does this special triangle
have?
Which of these terms may confuse children?
What is the name of this special triangle?
3 lines of symmetry are shown below for the triangle
The lines are referred to as l, m, and n.
2 colors are added here to show half the triangle folds
onto the other colored half. Assume the original interior
was white in color.
The red half folds onto the orange half so that both halves
match. This makes m a line of symmetry.
What kind of line symmetry is this?
l
m
n
Do all triangles have 3 lines of symmetry?
If not, draw ones with 0, 1, 2, and 4 lines of symmetry.
(if possible)
Use drawing and the Mira or paper folding and cutting to
study the lines of symmetry of famous quadrilaterals.
Some Famous quadrilaterals - 4-sided polygons
a) Described related to number of parallel sides
Trapezoid
Right trapezoid
Isosceles trapezoid
Parallelogram
b) Described related to all angles being congruent
?
c) Described related to all sides being congruent
?
d) Described related to both b and c being true
?
Make a Venn diagram showing the relationship of all
trapezoids, parallelograms, and rectangles in the
universe of quadrilaterals.
Angle and Regular Polygon Review
A popular measurement unit is the degree. There are
360 degrees in a circle (full turn).
There are half as many degrees in a half circle.
So 180 degrees in a straight angle.
A quarter circle has one-fourth the degrees of a full circle.
Such a 90 degree angle is called a right angle.
It is often shown with a small square corner near the
vertex of a right angle.
Angles that are less than 90 degrees are called _?_angles.
Draw such an angle:
Angles that are greater than 90 degrees are called
_?_angles. Some curricula also define __?__ angles as
larger than 180 degrees.
Between 90 and 180
Greater than 180
Polygon Terms Review
Polygons: simple closed 2-d shapes made up of straight
line segments for sides.
Famous Triangles
3-sided polygons
named for kinds of angles
acute triangles
right triangles
obtuse triangles
named for possible congruent side lengths
scalene triangle – no sides are congruent
isosceles triangle - 2 sides are congruent
equilateral triangle – all 3 sides are congurent
These may be combined for more detailed descriptions.
Draw an obtuse isosceles triangle.
Regular Polygons
A regular polygon is a polygon where all the interior
angles are congruent (same measurement) and all the
sides are congruent.
Regular triangle:
Draw a regular 2d shape
An equiangular polygon is a polygon where all the
interior angles are congruent (same measurement).
An equilateral polygon is a polygon where all the sides
are congruent (same length measurement).
Sketch examples to help you decide which of these are
true statements. (may want to focus on quadrilaterals and
triangles first)
1. A regular polygon is equilateral or equiangular.
2. A regular polygon is equilateral and equiangular.
3. All equilateral polygons are regular polygons.
4. All equiangular polygons are regular polygons.
5. All equilateral polygons are equiangular polygons.
Draw a Venn diagram showing the relationship of regular
polygons, equiangular polygons, and equilateral polygons.
Use the universe of all polygons.
Next draw an example sketch of a polygon that would go
into each region of the Venn diagram.