Geometry Review
Solid Shapes
Solid shapes have three parts:
faces, edges, and vertices. Look at the
shape below to see what each is.
vertex
face
edge
Note: Faces must be flat!
Solid Shapes
A cylinder has 2 faces and 2 edges.
face
edge
Solid Shapes
A cube has 6 faces, 12 edges and 8 vertices.
edge
face
vertex
Solid Shapes
A cone has 1 face, 1 vertex and 1 edge.
face
face(on
bottom)
edge
Solid Shapes
A square pyramid has 5 faces, 8 edges,
and 5 vertices.
vertex
edge
face
Solid Shapes
A sphere has no faces, edges, or
vertices, but we love it anyway!
Solid Shapes
A rectangular prism has 6 faces, 12 edges,
and 8 vertices, just like a square.
face
edge
vertex
Circles
Circles are named by their center point.
They have diameters, which are lines
that cross through the center point and
go from one side of the circle to the
other. They also have radii (plural of
radius) which go from the center point to
a point on the circle.
Rotational Symmetry
 If you can rotate (or turn) a figure around
a center point by fewer than 360° and the
figure appears unchanged, then the
figure has rotation symmetry. The point
around which you rotate is called the
center of rotation, and the smallest angle
you need to turn is called the angle of
rotation.
Rotational Symmetry
Perimeter and Area
 Perimeter
 The sum of the length of all the sides of a polygon.
 Area
 The number of square units needed to cover a
surface. (INSIDE)
Perimeter and Area
 Area= Base* Height
 Perimeter= L+L+W+W
Perimeter and Area
 Area = ½ (a+b) * h
 Perimeter = a+b+c+d
Area and Perimeter
 Area = ½ base* height
 Perimeter= Side + Side + Side
H
Circles
The name of this circle is B.
B
Circles
This is a radius. It is named AB or BA.
A
B
Circles
Below is the diameter of the circle. It is
named CD or DC.
B
C
D
Circles
A diameter is made up of two radii. So to
find the length of the diameter, you just
double the length of a radius.
2”
C
B
If the length of
the radius is 2
inches, the
D length of the
diameter is 4
inches.
Polygons
A polygon is a closed figure with
straight sides. The are classified by the
number of sides they have.
3 sides – triangle
4 sides – quadrilateral
5 sides – pentagon
6 sides – hexagon
8 sides - octagon
If all of the sides are the same length, it is called a
regular polygon. If they are not, it is called an
irregular polygon.
Polygons
These are all triangles because they
have 3 sides.
Polygons
These are all quadrilaterals because they
have 4 sides.
Triangles
Triangles are classified in two ways: by the
length of their sides, and by their angles.
Sides
 Equilateral – all 3 sides the same
 Isosceles – 2 sides the same
 Scalene – no side the same
Angles
 Right – one right angle
 Obtuse – one obtuse angle
 Acute – all three angles acute
Triangles
These are all right triangles because they
each have one right angle.
Triangles
These are all acute triangles because all
of the angles are acute.
Triangles
These are all obtuse triangles because
the have one obtuse angle.
Triangles
These are all equilateral triangles
because all 3 sides are congruent.
Triangles
These are all isosceles triangles
because they have 2 congruent sides.
Triangles
These are all scalene triangles because
none of the sides are congruent.
Symmetry
A shape has symmetry if you can draw a
line so that when the shape is folded ont
the line, the sides will match exactly.
This shape has
symmetry.
This shape does not.
Symmetry
The shape below does not have a line of
symmetry.
Symmetry
The shape below has two lines of
symmetry.
Congruence
Shapes are congruent if the are same size
and shape.
These two shapes are congruent.
These two shapes are not.
Congruence
The shapes below are also congruent. It’s
just that they are not facing the same
way.
Similarity
Two shapes are similar if the are the same
shape but not the same size.
These two shapes are
similar because they are
the same shape, but
one is smaller.
These two shapes are
not similar because they
even though they are
both rectangles, they
are not the same shape.
Similarity
Think about this - all circles and squares
are either congruent or similar.
Transformations
Transformations are ways of moving shapes. The
three we learned are:
flips
slides
turns
Transformations
Transformations
A flip is like a reflection. A shape flips over
itself.
These
are both
flips.
Transformations
A shape is turned when it rotates around a
corner.
These
are all
turns.
Transformations
Sliding means moving in any direction
without turning it or flipping it. These are
all slides.