5th Gr' Geometry

1
Geometric Shapes
Presentation by Connie Burton
2
Angles
3
angle
An angle is formed by two line segments or rays
that extend from the same endpoint.
4
The common endpoint of the two rays is called the
vertex of the angle.
vertex
5
Naming Angles
An angle is named by three points.
A
This angle can be named Angle ABC or Angle CBA
B
C
M
This angle can be named Angle MNO or Angle ONM
O
N
6
A
C
B
READ AS Angle ABC or Angle CBA WRITE AS
ABC or CBA
7
Naming Angles
M
O
N
READ AS Angle MNO or Angle ONM WRITE AS
MNO or ONM
8
Right Angles
90 degrees
A right angle is an angle that is formed by two
rays that are perpendicular to each other. The
angle measure is 90 degrees.
9
Obtuse Angles
90 degrees
An obtuse angle is greater than a right angle
(greater than 90 degrees).
10
Acute Angles
90 degrees
An acute angle is less than a right angle (less
than 90 degrees).
11
Straight Angles
A straight angle measures 180 degrees.
12
Polygons
square
pentagon
parallelogram
hexagon
octagon
A polygon is any closed figure that has straight
lines.
trapezoid
triangle
13
A triangle is a polygon that has three sides and
three angles.
14
The three angles of the triangle must add up to
equal 180 degrees.
60
60
60
60
180 degrees
60
60
15
The three angles of the triangle must add up to
equal 180 degrees.
90
50
50
40
40
180 degrees
90
16
Equilateral triangles
60
All sides are the same length.
4 in.
4 in.
60
60
All angles are the same measure.
4 in.
17
Isoceles triangle
30
At least two sides of the triangle are the same
length.
8 cm.
8 cm.
Two angles are the same measure.
75
75
4 cm.
18
Scalene triangle
No sides are the same length.
60
5 ft.
2 ft.
90
30
4 ft.
19
Right triangle
The triangle has one right angle.
90
Right angle
20
Acute triangle
30
All angles are acute angles.
75
75
21
Obtuse triangle
The triangle has one obtuse angle.
Obtuse angle
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Some triangles can be classified in two ways.
This is a right triangle. It has one right
triangle. This is a scalene triangle. No sides
are the same length.
23
This is an isoceles triangle. It has two sides
that are the same length. This is an acute
triangle. It has all acute angles.
24
This is an equilateral triangle. All sides are
the same length. All angles are the same
size. This is an acute triangle. All angles are
acute angles.
25
Other triangles