Download Angles, Angles Everywhere

Identify each object as containing an
acute, right, or obtuse angle
Right
Obtuse
Acute
The student will use angle measurement
to classify angles as acute, right, or
obtuse (TEKS 6.6a)
 The student will identify relationships
involving angles in triangles and
quadrilaterals (TEKS 6.6b)


Acute angle – an angle less than 90°

Angle – two rays with a common
endpoint

Degree – unit of measure for angles
°

Obtuse angle – an angle greater than
90°

Straight angle – an angle whose
measure is exactly 180°

Polygon – a geometric figure made up of
three or more line segments that
intersect only at their endpoints

Vertex (pl. vertices) – the common
endpoint of the two rays form an angle

Triangle – a polygon with three sides and
three vertices

Quadrilateral – a polygon with four sides
and four vertices

Square – a polygon with four equal sides
and four right angles

Rectangle – a polygon with four right
angles and four sides

Trapezoid – a quadrilateral with exactly
one pair of parallel sides

Parallelogram – a quadrilateral with
exactly two pairs of parallel sides

The sum of all angles in a triangle equals
180°
110°
80°
45°
25°
45°
90°
50°
45°
50°
80° + 50° + 50° = 180°
90° + 45° + 45° = 180°
110° + 45° + 25° = 180°
If we know that the sum of all angles in a
triangle equals 180°, then…
What is the measure of the missing angles?
72°
?
78°
72° + 78° + ? = 180°
180° - 150° = 30°
115°
45°
?
45°
45° + 45° + ? = 180°
180° - 90° = 90°
35°
?
115° + 35° + ? = 180°
180° - 150° = 30°
Since a square can be
divided into two
triangles, then…
Since a rectangle can
be divided into two
triangles, then…
180°
360°
180°
360°
180°
the sum of all angles in
a square is 360°,
because
180° + 180° = 360°
180°
the sum of all angles in
a rectangle is 360°,
because
180° + 180° = 360°
Since a parallelogram
can be divided into
two triangles, then…
Since a trapezoid can
be divided into two
triangles, then…
180°
180°
360°
180°
the sum of all angles in
a parallelogram is 360°,
because
180° + 180° = 360°
360°
180°
the sum of all angles in
a trapezoid is 360°,
because
180° + 180° = 360°
If we know that the sum of all angles in a
square, rectangle, parallelogram, and
trapezoid equals 180°, then…
What is the measure of the missing angles?
90°
90°
90°
90°
110°
?
90° + 90° + 90° + ? = 180°
360° - 270° = 90°
?
?
70°
90°
110°
90°
90° + 90° + 90° + ? = 180°
360° - 270° = 90°
?
110°
110° + 70° + 110° + ? = 180°
360° - 290° = 70°
70°
70°
110° + 70° + 70° + ? = 180°
360° - 250° = 110°
You will be going out onto the playground
and will search for “real life” examples of
acute, obtuse, and right angles.
 Separate into your assigned groups
 Decide which group member will be the
record keeper
 Head out to the playground, you will
have 15 minutes to gather as many items
as you can
Acute
(less than 90°)
Right
(90°)
Obtuse
(more than 90°)
Wheelchair ramp
Window pane
Tree branches
Swing set
Basketball court
Slide roof
Moon climber
Slide
Baseball fence
Soccer goal
Door
Fence line
Baseball base (top)
Fence line
School building
Football field
Football goal
Bleachers
School building