Download Tuesday, March 4 Chapter13-4 Two Dimensional Figures

Tuesday, March 4
Chapter13-4
Two Dimensional Figures
Two Dimensional Figures
Objective: To understand sides and angles of
polygons.
Two Dimensional Figures
A polygon is a simple closed, two dimensional
figure with three or more sides.
The number of sides will determine a
polygon’s name.
Two Dimensional Figures
When all of the sides and angles of a polygon
are congruent, the polygon is a regular
polygon.
If the sides are not congruent, the polygon is
irregular.
Two Dimensional Figures
A triangle has three sides and three angles.
The inside angles of a triangle will always add
to 180°.
Two Dimensional Figures
Certain triangles have specific names:
A scalene triangle has no congruent sides.
Two Dimensional Figures
Certain triangles have specific names:
An isosceles triangle has two sides congruent.
Two Dimensional Figures
Certain triangles have specific names:
An equilateral triangle has all sides congruent.
Two Dimensional Figures
A quadrilateral has four sides.
The inside angles of a quadrilateral will always
add to 360°.
Two Dimensional Figures
Certain quadrilaterals have specific names:
A rectangle has opposite sides that are
congruent and parallel, and all angles are
right angles.
Two Dimensional Figures
Certain quadrilaterals have specific names:
A square has all sides that are congruent and
parallel, and all angles are right angles.
Two Dimensional Figures
Certain quadrilaterals have specific names:
A parallelogram has opposite sides that are
congruent and parallel, and opposite angles
are congruent.
Two Dimensional Figures
Certain quadrilaterals have specific names:
A rhombus has all sides that are congruent,
opposite sides are parallel and opposite
angles are congruent.
Two Dimensional Figures
A pentagon has five sides.
The inside angles of a pentagon will always
add to 540°.
Two Dimensional Figures
A hexagon has six sides.
The inside angles of a hexagon will always add
to 720°.
Two Dimensional Figures
A heptagon has seven sides.
The inside angles of a heptagon will always
add to 900°.
Two Dimensional Figures
A octagon has eight sides.
The inside angles of a octagon will always add
to 1080°.
Two Dimensional Figures
A nonagon has nine sides.
The inside angles of a nonagon will always add
to 1260°.
Two Dimensional Figures
A decagon has ten sides.
The inside angles of a decagon will always add
to 1440°.
Two Dimensional Figures
The formula to find the sum of the inside
angles of any polygon is the number of sides
minus 2 then multiply by 180, or (n-2)180.
Two Dimensional Figures
Identify the polygon and determine if it is
regular or irregular.
Two Dimensional Figures
Identify the polygon and determine if it is
regular or irregular.
Irregular quadrilateral
(parallelogram)
Since the polygon has 4 sides it is a
quadrilateral. Since all sides are not
congruent, it is irregular.
Two Dimensional Figures
Identify the polygon and determine if it is
regular or irregular.
Irregular quadrilateral
(parallelogram)
Three of the inside angles add to 333˚. What
is the remaining angle?
Two Dimensional Figures
Identify the polygon and determine if it is
regular or irregular.
Irregular quadrilateral
(parallelogram)
Three of the inside angles add to 333˚. What
is the remaining angle? 360˚ – 333˚ = 27˚
Two Dimensional Figures
Identify the polygon and determine if it is
regular or irregular.
Two Dimensional Figures
Identify the polygon and determine if it is
regular or irregular.
irregular hexagon
Since the polygon has 6 sides it is a hexagon.
Since all sides are not congruent, it is
irregular.
Two Dimensional Figures
Identify the polygon and determine if it is
regular or irregular.
irregular hexagon
Five of the inside angles add to 685˚. What is
the remaining angle?
Two Dimensional Figures
Identify the polygon and determine if it is
regular or irregular.
irregular hexagon
Five of the inside angles add to 685˚. What is
the remaining angle? 720˚ – 685˚ = 35˚
Two Dimensional Figures
Identify the polygon and determine if it is
regular or irregular.
Two Dimensional Figures
Identify the polygon and determine if it is
regular or irregular.
Regular quadrilateral
(square)
Since the polygon has 4 sides it is a
quadrilateral. Since all sides are congruent,
it is regular.
Two Dimensional Figures
Identify the polygon and determine if it is
regular or irregular.
Two Dimensional Figures
Identify the polygon and determine if it is
regular or irregular.
Irregular triangle
(isosceles)
How do we know two sides are congruent?
Two Dimensional Figures
Identify the polygon and determine if it is
regular or irregular.
Irregular triangle
(isosceles)
Since the opposite angles are the same, the
sides are the same length.
Two Dimensional Figures
Identify the polygon and determine if it is
regular or irregular.
Two Dimensional Figures
Identify the polygon and determine if it is
regular or irregular.
Irregular pentagon
Since the polygon has 5 sides it is a
pentagon. Since all sides are not congruent,
it is irregular.
Two Dimensional Figures
Identify the polygon and determine if it is
regular or irregular.
Irregular pentagon
Four of the inside angles add to 497˚. What is
the remaining angle?
Two Dimensional Figures
Identify the polygon and determine if it is
regular or irregular.
Irregular pentagon
Four of the inside angles add to 497˚. What is
the remaining angle? 540˚ – 497˚ = 43˚
Two Dimensional Figures
Identify the polygon and determine if it is
regular or irregular.
Two Dimensional Figures
Identify the polygon and determine if it is
regular or irregular.
Irregular triangle
(scalene)
Since the polygon has 3 sides it is a triangle.
Since all sides are not congruent, it is
irregular (scalene).
Two Dimensional Figures
Identify the polygon and determine if it is
regular or irregular.
Irregular triangle
(scalene)
Two of the inside angles add to 129˚. What is
the remaining angle?
Two Dimensional Figures
Identify the polygon and determine if it is
regular or irregular.
Irregular triangle
(scalene)
Two of the inside angles add to 129˚. What is
the remaining angle? 180˚ – 129˚ = 51˚
Two Dimensional Figures
What do you say when you see an empty
parrot cage?
Two Dimensional Figures
What do you say when you see an empty
parrot cage?
polygon
Two Dimensional Figures
Agenda Notes –
Homework – Practice Skills 13-4
Due Wednesday, March 5
Chapter 13 Test
Monday, March 10