Section outline

  • Classifying Angles
    ::分类分类角度

    Angles can be grouped into four different categories.
    ::角可以分为四大类。

    Straight Angle : An angle that measures exactly 180 .
    ::直角 : 精确测量 180 的角 。

    Acute Angles : Angles that measure between 0 and up to but not including 90 .
    ::急性角:测量 0至最高但不包括 90之间的角。

    Obtuse Angles: Angles that measure more than 90 but less than 180 .
    ::阻力角: 测量超过 90 的角, 但小于 180 的角 。

    Right Angle : An angle that measures exactly 90 .
    ::右角: 精确测量 90 的角 。

    This half- square marks right, or 90 , angles. When two lines intersect to form four right angles, the lines are perpendicular . The symbol for perpendicular is .
    ::这个半平方标记右转, 或 90 , 角度。 当两条线交叉形成四个右角时, 直线是垂直的。 直线的符号是 。

    Even though all four angles are 90 , only one needs to be marked with the half-square. l m is read line l is perpendicular to line m .
    ::尽管所有四个角度都是90,但只需用半平方标记一个。Im读行I与m直线垂直。

    What if you were given the degree measure of an angle? How would you describe that angle based on its size?
    ::如果给您一个角度的度量度呢? 您如何根据角度的大小描述该角度 ?

    Examples
    ::实例

    Example 1
    ::例1

    What type of angle is  90 ?
    ::90是哪种角度?

    The angle measure is exactly 90 , so it is right.
    ::角度量度正好是90,所以是正确的。

    Example 2
    ::例2

    What type of angle is 84 ?
    ::84是什么样的角度?

    84 is less than 90 , so it is acute.
    ::84小于90,所以是急性。

    Example 3
    ::例3

    What type of angle is 165 ?
    ::165是哪种角度?

    165 is greater than 90 , but less than 180 , so it is obtuse.
    ::165比90还大,但小于180,所以是模糊的。

    Example 4
    ::例4

    Name the angle and determine what type of angle it is.
    ::命名角度并确定是哪种角度。

    The vertex is U . So, the angle can be T U V or V U T . To determine what type of angle it is, compare it to a right angle.
    ::顶点是 U。 所以, 角度可以是 TUV 或 VUT 。 要确定是哪种角度, 请将其与右角度比较 。

    Because it opens wider than a right angle and is less than a straight angle, it is obtuse .
    ::因为它打开的宽度大于一个右角度, 也小于一个直角, 它就是模糊的。

    Review
    ::回顾

    For exercises 1-4, determine if the statement is true or false.
    ::练习 1-4 确定声明是真实的还是虚假的。

    1. Two angles always add up to be greater than 90 .
      ::两个角度加起来总大于90。
    2. 180 is an obtuse angle.
      ::180是个隐蔽的角度
    3. 180 is a straight angle.
      ::180是直角
    4. Two perpendicular lines intersect to form four right angles.
      ::两条垂直直线交叉,形成四个右角。

    For exercises 5-10, state what type of angle it is.
    ::对于演习5-10,请说明是何种角度。

    1. 55
    2. 92
    3. 178
    4. 5
    5. 120
    6. 73

    In exercises 11-15, use the following information: Q is in the interior of R O S . S is in the interior of Q O P . P is in the interior of S O T . S is in the interior of R O T and m R O T = 160 ,   m S O T = 100 , and m R O Q = m Q O S = m P O T .
    ::在11-15演习中,请使用以下信息:Q在QROS内地;S在QOP内地;P在QSOT内地;S在QROT内地;MZOT=160;MQSOT=100;和MQROmOS=mPOT。

    1. Make a sketch.
      ::做一个草图。
    2. Find m Q O P .
      ::去找妈妈
    3. Find m Q O T .
      ::找妈妈。
    4. Find m R O Q .
      ::去找麦奎克
    5. Find m S O P .
      ::找到MSOP。

    Review (Answers)
    ::回顾(答复)

    To see the Review answers, open this and look for section 1.6. 
    ::阅读《评论》的答复,打开这个打开,看看第1.6节。

    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 。