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  • 反射对称

    Reflection Symmetry
    ::反射对称

    A line of symmetry is a line that passes through a figure such that it splits the figure into two congruent halves such that if one half were folded across the line of symmetry it would land directly on top of the other half.
    ::对称线是一条穿过一个数字的线,它把数字分成两个相近的两半,这样,如果将一半折叠在对称线上,它就会直接降落在另一半上方。

    Reflection symmetry is present when a figure has one or more . These figures have reflection symmetry:
    ::当数字有一个或一个以上时,反射对称即出现。

    These figures do not have reflection symmetry:
    ::这些数字不具有反射对称性:

    lesson content

    What if you had a six-pointed star, you drew a line down it, and then you folded it along that line? If the two sides of the star lined up, what would that mean about the line?
    ::如果你有一个六点的恒星, 你画了一条线,然后把它折叠在这条线上呢?如果恒星的两面排成一排,那这是什么意思?

    Examples
    ::实例

    Example 1
    ::例1

    Find all lines of symmetry for the shape below.
    ::查找下方形状的所有对称行 。

    Draw lines through the figure so that the lines perfectly cut the figure in half. This figure has eight lines of symmetry.
    ::在图中绘制线条,使线条将图数完全切成两半。此图有八行对称。

    Example 2
    ::例2

    Find all lines of symmetry for the shape below.
    ::查找下方形状的所有对称行 。

    You cannot draw lines through the figure so that the lines perfectly cut the figure in half, so this figure has no lines of symmetry.
    ::您无法在图中绘制线条, 以使线条将图段完全切成两半, 因此此图没有对称线 。

    Example 3
    ::例3

    Find all lines of symmetry for the shape below.
    ::查找下方形状的所有对称行 。

    This figure has two lines of symmetry.
    ::这个数字有两条对称线。

    Example 4
    ::例4

    Does the figure below have reflection symmetry?
    ::下图是否反映对称?

    lesson content

    Yes, this figure has reflection symmetry.
    ::是的,这个数字是反射对称的。

    lesson content

    Example 5
    ::例5

    Does the figure below have reflection symmetry?
    ::下图是否反映对称?

    Yes, this figure has reflection symmetry.
    ::是的,这个数字是反射对称的。

    Review
    ::回顾

    Determine whether each statement is true or false.
    ::确定每一声明是真实的还是虚假的。

    1. All right triangles have line symmetry.
      ::所有右三角都有直线对称。
    2. All isosceles triangles have line symmetry.
      ::所有等分三角形均具有直线对称性。
    3. Every rectangle has line symmetry.
      ::每个矩形都有线对称
    4. Every rectangle has exactly two lines of symmetry.
      ::每个矩形都有两条对称线
    5. Every parallelogram has line symmetry.
      ::每个平行图都有直线对称。
    6. Every square has exactly two lines of symmetry.
      ::每个广场都有两条对称线
    7. Every regular polygon has three lines of symmetry.
      ::每个常规多边形都有三行对称。
    8. Every sector of a circle has a line of symmetry.
      ::圆的每个区段都有对称线。

    Draw the following figures.
    ::绘制下图。

    1. A quadrilateral that has two pairs of congruent sides and exactly one line of symmetry.
      ::一种四边形 具有两对相近的两面 和一对对称
    2. A figure with infinitely many lines of symmetry.
      ::一个无穷无尽的对称线的数字。

    Find all lines of symmetry for the letters below.
    ::查找以下字母的所有对称行 。

    Determine if the words below have reflection symmetry.
    ::确定以下文字的反射对称值。

    1. OHIO
      ::俄、俄、俄、俄、俄、俄、俄
    2. MOW
      ::呜
    3. WOW
      ::哇哇
    4. KICK
      ::鸡鸡
    5. pod
      ::缓冲

    Trace each figure and then draw in all lines of symmetry.
    ::追踪每个图,然后绘制所有对称线。

    Determine if the figures below have reflection symmetry. Identify all lines of symmetry.
    ::确定下图是否有反射对称。 标明所有对称行 。

    Review (Answers)
    ::回顾(答复)

    Click to see the answer key or go to the Table of Contents and click on the Answer Key under the 'Other Versions' option.
    ::单击可查看答题键, 或转到目录中, 单击“ 其他版本” 选项下的答题键 。