A polygon is a closed figure made of three or more straight line segments sides' A regular polygon i - PowerPoint PPT Presentation

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A polygon is a closed figure made of three or more straight line segments sides' A regular polygon i

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... size, they are congruent angles. For example, all right angles are congruent. ... similar figures have congruent angles, but the sides might not be congruent. ... – PowerPoint PPT presentation

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Title: A polygon is a closed figure made of three or more straight line segments sides' A regular polygon i


1
  • A polygon is a closed figure made of three or
    more straight line segments (sides). A regular
    polygon is a polygon that has equal sides and
    equal angles.

Gr5-U5-L1
2
  • We can identify different polygons by looking for
    their properties. Properties of polygons include
    sides (or edges) and angles (or corners). For
    example, we see that a rectangle has 2 pairs of
    parallel sides and 4 square angles, and that is
    how we know it is a rectangle. If we see a
    rectangle with 4 equal sides, we know it is a
    square.

Gr5-U5-L1
3
  • Polygons are often named for the number and kinds
    of sides and angels they have. For example,
    triangles have 3 angles, quadrilaterals have 4
    sides, parallelograms are quadrilaterals with 2
    pairs of parallel sides, pentagons have 5 sides
    and 5 angles, hexagons have 6 sides and 6 angles,
    and octagons have 8 sides and 8 angles, etc.

Gr5-U5-L1
4
  • Triangles can be classified by the size of their
    angles. Obtuse triangles have one obtuse angle -
    one angle larger than 90º. Acute triangles have
    all three acute angles - all three angles smaller
    than 90º. Right triangles have one right angle -
    one 90º angle.

Gr5-U5-L2
5
  • Triangles can be classified by the sides.
    Equilateral triangles have all three sides equal.
    Isosceles triangles have two equal sides.
    Scalene triangles have no equal sides.

Gr5-U5-L2
6
  • Triangles are the most basic polygons. All other
    polygons can be divided into triangles.

Gr5-U5-L2
7
  • Mathematicians have agreed to divide a circle
    into 360º. In other words, there are 360º around
    the midpoint, or center, of a circle. Any angle
    is a portion of a circle. If an angle is not
    part of an actual circle, a circle could be
    constructed around it with the vertex of the
    angles as the midpoint or center.

Gr5-U5-L3
8
  • To measure an angle, we place the vertex at the
    center of a circle and measure the number of
    degrees around the center of the circle between
    the two sides of the angle. That means that all
    angles measure 360º or less because angles are
    parts of a circle.

Gr5-U5-L3
9
  • The sum of the angles of any triangle is 180º.
  • Sides of a polygon are name by their end points,
    which are the vertices of the polygon. For
    example, the side between vertex A and vertex B
    is called side AB.

Gr5-U5-L3
10
  • Angles can be named three ways. An angle can be
    named by its vertex. For example, the vertex of
    ?A is at point A. An angle can be named by its
    sides two ways. For example, if the sides of ?A
    are side AB and side AC, then the angle would be
    named ?BAC or ?CAB. The vertex must always be
    the middle letter in the angle name.

Gr5-U5-L3
11
  • A protractor is a tool for measuring the number
    of degrees in an angle.
  • Before you measure an angle, decide whether it is
    acute or obtuse. Remember, an acute angle is
    less than 90º. Use the scale on the protractor
    that makes sense for the size of that angle.

Gr5-U5-L3
12
  • Changing the lengths of the sides of an angle
    does not change the size of the angle.

Gr5-U5-L3
13
  • Changing the lengths of the sides of an angle
    does not change the size of the angle.
  • Sides of a polygon are named by their end points,
    which are their vertices of the polygon. For
    example, the side between vertex W and vertex X
    is called side WX.

Gr5-U5-L4
14
  • Angles can be named three ways. An angle can be
    named by its vertex. For example, the vertex of
    ?W is at point W. An angle can be named by its
    sides two ways. For example, if the sides of ?W
    are side WZ and side WX, then the angle would be
    named ?XWZ or ?ZWX. The vertex must always be
    the middle letter in the angle name.

Gr5-U5-L4
15
  • A compass is a tool for constructing circles, or
    arcs which are parts of circles.

Gr5-U5-L4
16
  • A circle has a center, circumference, radius, and
    diameter. The circumference is the distance
    around the circle. The radius of a circle is a
    straight line from the center to any point on the
    circumference. The diameter of a circle is a
    straight line from one point on the circumference
    through the center of the circle to another point
    on the circumference.

Gr5-U5-L4
17
  • If angles are the same size, they are congruent
    angles. For example, all right angles are
    congruent.
  • If line segments are the same length, they are
    congruent line segments. For example, all the
    sides of a square are congruent.

Gr5-U5-L5
18
  • Congruent figures are figures that are the same
    size and shape. In other words, in congruent
    figures, the corresponding angles are congruent
    and the corresponding sides are congruent. For
    example, two six-inch squares are congruent.

Gr5-U5-L5
19
  • Similar figures are figures that are the same
    shape, but are not necessarily the same size. In
    other words, similar figures have congruent
    angles, but the sides might not be congruent.
    The corresponding sides are in the same ration.
    For example, a right triangle with sides of 1
    in., 2 in., and 21/4 in. is similar to a right
    triangle with corresponding sides of 2 in., 4
    in., and 41/2 in.

Gr5-U5-L5
20
  • All circles are similar because they are the same
    shape and have 360º around their centers. Only
    circles with the same radius or diameter are
    congruent.

Gr5-U5-L5
21
  • When we change the position of a shape, we call
    that a transformation. A shape in a different
    position is not a different shape. The position
    of the object is transformed, not its shape.

Gr5-U5-L6
22
  • There are three basic transformations slides
    (translations), turns (rotations), and flips
    (reflections).
  • A slide, or translation, is when a shape is moved
    horizontally or vertically.
  • A turn, or rotation, is when an object is rotated
    either clockwise or counterclockwise.

Gr5-U5-L6
23
  • A flip, or reflection, is when an object is
    turned over to create a mirror image. Flips are
    often used to create symmetrical figures.

Gr5-U5-L6
24
  • A figure is symmetrical if it can be folded
    either mentally or physically, into two congruent
    halves positioned so that one half lies exactly
    on top of the other half. In other words, a
    figure is symmetrical if one half is a reflection
    of the other. A line of symmetry is a straight
    line lying exactly where a figure can be folded
    into two symmetrical halves.

Gr5-U5-L6
25
  • For a figure to be symmetrical, it needs two
    properties
  • 1. Both halves need to be
  • congruent.
  • 2. The halves need to be
  • positioned so that they are
  • reflections of each other.

Gr5-U5-L6
26
  • Tessellations are a kind of pattern. When you
    cover an area with a pattern of polygons or other
    closed figures with no gaps and no overlapping,
    you have made a tessellation. For example, a
    tile floor or a brick wall are tessellations.

Gr5-U5-L7
27
  • Coordinates are a pair of numbers that locate a
    point in relation to the axes. Coordinates are
    always written in the same order so we call them
    ordered pairs. The first coordinate tells the
    sideways location and the second coordinate tells
    the up and down location.

Gr5-U5-L8
28
  • Coordinates are a pair of numbers that locate a
    point in relation to the axes. Coordinates are
    always written in the same order so we call them
    ordered pairs. The first coordinate tells the
    sideways location and the second coordinate tells
    the up and down location.

Gr5-U5-L8
29
  • The distance around a polygon or other
    two-dimensional shape is the perimeter.
  • The length of the perimeter of any polygon is the
    sum of the lengths of all its sides. In other
    words, P sum of the sides.

Gr5-U5-L8
30
  • The distance around a circle is called the
    circumference.
  • Pi is a number that mathematicians use to find
    the circumference and area of circles. Pi is
    represented by the symbol (?). Pi (?) equals
    about 3.14.
  • The circumference of a circle equals pi (?) times
    the diameter
  • C ?d.

Gr5-U5-L11
31
  • Area has two dimensions length and width. We
    measure area in square units of measure such as
    square inches or square centimeters because
    square units of measure indicate length and
    width, not just length.

Gr5-U5-L11
32
  • Figures with the same perimeters can have
    different areas. The closer the sides are to
    each other in length, the larger the area
    enclosed. For example, if a square and a
    rectangle have the same perimeter, the square
    will have the larger area.

Gr5-U5-L12
33
  • We find the area of a trapezoid by dividing it
    into a rectangle and one or two triangles,
    finding the areas of the component parts, and
    then adding to find the total area.
  • We find the area of a square or rectangle by
    multiplying the length by the width. The formula
    for finding the area of a rectangle is A 1 x w.

Gr5-U5-L12
34
  • We find the area of a triangle by multiplying the
    height by the base and dividing that amount in
    half. The formula for finding the area of a
    triangle is A 1/2(b x h).

Gr5-U5-L12
35
  • We estimate the area of irregular figures by
    counting the squares and partial squares inside
    the perimeter of the figure.
  • When we estimate with fractions, we decide
    whether a fraction is near 0, 1/2, or 1. To
    estimate the area of an irregular shape, we need
    to look at each partial square and decide whether
    it is about 0 squares, about 1/2 square, or about
    1 square.

Gr5-U5-L13
36
  • Plane figures have two dimensions length and
    width. Solid figures take up space and have
    three dimensions length, width, and height.

Gr5-U5-L14
37
  • Polyhedra and three-dimensional figures with
    curved surfaces are two kinds of solid figures.
    A solid figure with sides that are polygons is
    called a polyhedron. Polyhedra is the plural of
    polyhedron. Polyhedra include all kinds of
    prisms and pyramids. Solid figures with curved
    surfaces include spheres, cylinders, and cones.

Gr5-U5-L14
38
  • Polyhedra have faces (sides), edges (lines where
    the sides join together), and vertices (vertex is
    the singular) or corners (points where edges
    meet). A cylinder has a curved surface and two
    circular or oval face or base, and a vertex. A
    sphere has only a curved surface.

Gr5-U5-L14
39
  • A pyramid has triangular faces and any polygon as
    a base. A prism has square or rectangular faces
    and a pair of any congruent polygons as bases.
    Each prism and pyramid is classified by the shape
    of its base or bases.

Gr5-U5-L14
40
  • The surface area of a solid figure is the sum of
    the areas of all the faces or surfaces of the
    solid figure because these faces or surfaces
    cover the outside, or surface, of the figure.

Gr5-U5-L15
41
  • The amount of space inside a solid figure is its
    volume. Volume has three dimensions length,
    width, and height. Since volume has three
    dimensions, it is measured in cubic units of
    measure.

Gr5-U5-L15
42
  • Volume is measured by finding the number of real
    or imaginary identical cubes that fit in a space.
    For example, if four 1-centimeter cubes make a
    rectangular prism is 4 cubic centimeters.

Gr5-U5-L15
43
  • Volume is measured by finding the number of real
    or imaginary identical cubes that fit in a space.
    For example, if sixteen 1-centimeter cubes fit
    in a box, the volume of the box is 16 cubic
    centimeters.

Gr5-U5-L16
44
  • The volume of a rectangular prism is found by
    multiplying the length by the width by the
    height. The formula for finding the volume of a
    rectangular prism is V 1 x w x h.
  • Since the volume has three dimensions (length,
    width, and height), it is measured in cubic units
    of measure.

Gr5-U5-L16
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