Section outline

  • lesson content

    Susan has taken a keen interest in Geometry and wants to expand her knowledge of angles . While looking through a magazine she saw the following picture:
    ::Susan对几何学非常感兴趣,想扩大对角度的了解。

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    Susan knew the angles had a relationship but she couldn’t remember what they were called or how she could use the information to figure out the size of the angles.
    ::Susan知道这些角度有某种关系, 但她不记得这些角度叫什么,

    How can Susan use the given measures of the angles to find the measure of each angle in degrees?
    ::Susan如何使用给定角度的量度来找到每个角度的度量?

    In this concept, you will learn to identify adjacent and .
    ::在这一概念中,你将学会识别相邻和.。

    Adjacent and Vertical Angles
    ::相邻和垂直角

    When two straight lines intersect each other, four angles are created such that the point of intersection is the vertex for each angle. If two of the angles have a common vertex and share a common side they are called adjacent angles . The adjacent angles formed by two intersecting lines are supplementary which means the sum of their measures is 180 .
    ::当两条直线相互交错时,将创建四个角度,使交叉点为每个角度的顶点。如果两个角度有一个共同的顶点并有一个共同的侧面,它们就被称为相邻角度。两个交叉线形成的相邻角度是补充性的,这意味着其测量量的总和是180\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\

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    2  and 4  are adjacent angles. The angles are next to each other, have common vertex and share the common side.  m 2 + m 4 = 180
    ::\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\180\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\

    These are not the only adjacent angles formed by the intersection of the lines. The remaining pairs of adjacent angles are shown below:
    ::这些角度并非线条交叉点形成的唯一相邻角度。 其余的对相邻角度如下所示:

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    When two lines intersect, vertical angles , which are non-adjacent angles are also formed. There are two pairs of vertical angles. These angles also have a common vertex but never share a common side. The vertical angles are opposite each other and are equal in measure.
    ::当两个线条交叉时, 垂直角度( 即非相邻角度) 也会形成。 有两对垂直角度。 这些角度也有一个共同的顶点, 但从不共享共同的侧面。 垂直角度是相互对立的, 在量上是相等的 。

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    There are two pair of vertical angles:
    ::有两对垂直角度:

    1  and  2 3 and  4 . The  m 1 = m 2  and   m 3 = m 4 .
    ::1和2;3和4。 m1=m2和m3=m4。

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    Let’s apply all this information about angles to a problem.
    ::让我们将所有这些关于角度的信息应用到问题上。

    Using the following diagram , calculate the measures of the remaining three angles.
    ::使用下图计算其余三个角度的度量。

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    First, state the relationship between J K L  and one other angle.

    J K L  and L K N  are adjacent angles.
    ::首先,请说明jKL与其他角度之间的关系。jKL和LKN是相邻角度。

    Next, use this relationship to calculate the measure of L K N .
    ::下一步,使用此关系来计算 LKN 的度量 。

    m J K L + m L K N = 180

    ::@ mJKL+mLKN=180

    Next, substitute 43 , for the measure of J K L  in the equation.
    ::下面换43 以测量方程式中的jKL

    m J K L + m L K N = 180 43 + m L K N = 180

    ::@ mJKL+mLKN=18043LKN=180

    Next, subtract 43  from both sides of the equation to solve for m M K N .
    ::下一步,从方程的两侧减去43 以解答 mMKN 。

    43 + m L K N = 180 43 43 + m L K N = 180 43 m L K N = 137

    ::-==YTET -伊甸园字幕组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=- 翻译组=-

    First, state another relationship between J K L  and another angle.
    ::首先,说明ZQKL和另一个角度之间的另一关系。

    J K L  and M K N  are vertical angles.
    ::@JKL和QMKN是垂直角度。

    Next, use this relationship to calculate the measure of  M K N .
    ::下一步,使用此关系来计算 QMKN 的度量 。

    m J K L = m M K N

    ::@ mjKL=mMKN

    Next, substitute 43 , for the measure of  J K L  in the equation.
    ::下面换43 以测量方程式中的jKL

    m J K L = m M K N 43 = m M K N

    ::@ mjKL=m @MKN43 @mKN @MKN @MKN @MKN

    First, state the relationship between the remaining angle and one other angle.
    ::首先,说明剩余角与其他角之间的关系。

    L K N  and J K M  are vertical angles.
    ::@LKN和QJKM是垂直角度。

    Next, use this relationship to calculate the measure of J K M .
    ::下一步,使用此关系来计算 JKM 的度量 。

    m L K N = m J K M

    ::@ mLKN=mJKM

    Next, substitute 137 , for the measure of L K N  in the equation.
    ::接下来, 替代137, 在方程式中测量 LKN 。

    m L K N = m J K M 137 = m J K M

    ::@ mLKN =mJKM137MQKM

    Examples
    ::实例

    Example 1
    ::例1

    Earlier, you were given a problem about Susan and her interest in Geometry.
    ::早些时候,你得到一个问题 关于苏珊和她对几何的兴趣。

    She needs to figure out the measure of two equal angles.
    ::她需要找出两个平等角度的度量

    The two given angles are opposite each other. These angles are vertical angles.
    ::给定的两个角度对立。 这些角度是垂直角度 。

    Susan can use the fact that vertical angles are equal in measure to calculate the measure of these angles.
    ::Susan可以使用垂直角度等量来计算这些角度的度量。

    First, write the relation between the two vertical angles such that 1 = ( 2 x 9 )  and  2 = ( x + 39 ) .
    ::首先,写下两个垂直角度之间的关系, 以便% 1 =( 2x- 9) 和% 2 =( x+39) * 。

    m 1 = m 2
     
    ::m1=m%2

    Next, substitute the values for each angle into the equation.
    ::接下来,替换方程式中每个角度的值。

    ( 2 x 9 ) = ( x + 39 )

    :sad2x-9) (x+39)

    Next, clear the parenthesis by multiplying both sides of the equation by one.
    ::接下来,通过将方程的两侧乘以一来清除括号。

    2 x 9 = x + 39

    ::2 - 9x+39

    Next, add 9 to both sides of the equation to group the constants on one side of the equation.
    ::接下来,在等式的两侧加9,将常数组合在等式的一边。

    2 x 9 = x + 39 2 x 9 + 9 = x + 39 + 9 2 x = x + 48

    ::2 -9x+392x999999992x=x+48

    Next, subtract ‘ x  from both sides of the equation to group the variables on one side of the equation.
    ::下一步,从方程的两侧减去 'x ' ,将变量组合在方程的一边。

    2 x = x + 48 2 x x = x x + 48 x = 48

    ::2x=x+482x-x=x-x+48x=48

    Use the value of the variable to calculate the measure of 1  and 2 .
    ::使用变量的值来计算 #% 1 和 # 2 的度量。

    1 = ( 2 x 9 )   and   2 = ( x + 39 ) 1 = ( 2 ( 48 ) 9 )   and   2 = ( 48 + 39 ) 1 = ( 96 9 )   and   2 = ( 48 + 39 ) 1 = 87   and   2 = 87

    ::1=(2x-9) 2=(x+39) 1=(2(48-9) 2=(48+39) 1=(96-9) 2=(48+39) 1=(96-9) 2=(48+39) 1=(87) 2=(87) 2=(87)

    The measures of the two vertical angles are equal.
    ::两个垂直角度的测量是相等的。

     

    Using the following diagram, calculate the measures of the remaining three angles.
    ::使用下图计算其余三个角度的度量。

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    First, state the relationship between  4  and one other angle.
    ::首先,说明4和另一个角度之间的关系。

    4  and 2  are vertical angles.
    ::4和2是垂直角度。

    Next, use this relationship to calculate the measure of 2 .
    ::接下来,使用此关系来计算 2 的度量。

    m 4 = m 2

    ::m4=m2

    Next, substitute 118 , for the measure of 4  in the equation.
    ::接下来,替换118,以测量方程式中的 4。

    m 4 = m 2 118 = m 2

    ::===================================================================================================================================================================================

    First, state another relationship between  4   and another angle.
    ::首先,说明4和另一个角度之间的另一关系。

    4  and  1   are adjacent angles.
    ::4和1是相邻角度

    Next, use this relationship to calculate the measure of 1 .
    ::下一步,使用此关系来计算 #% 1 的度量。

    m 4 + m 1 = 180


    ::m4+m1=180

    Next, substitute 118 , for the measure of 4  in the equation.
    ::接下来,替换118,以测量方程式中的 4。

    m 4 + m 1 = 180 118 + m 1 = 180

    ::m4+m1=1801181=180

    Next, subtract 118  from both sides of the equation to solve for  m 1 .
    ::接下来,从方程的两侧减去118 以解答 m1 。

    118 + m 1 = 180 118 118 + m 1 = 180 118 m 1 = 62

    ::118 118 1 = 180 118 1 = 118 1 = 62

    First, state the relationship between the remaining angle and one other angle.
    ::首先,说明剩余角与其他角之间的关系。

    1  and 3  are vertical angles.
    ::1和3是垂直角度。

    Next, use this relationship to calculate the measure of 3 .
    ::接下来,使用此关系来计算 3 的度量 。

    m 1 = m 3

    ::m1=m3

    Next, substitute 62 , for the measure of  1  in the equation.
    ::接下来,替换 62 , 以测量方程式中的 1 。

    m 1 = m 3 62 = m 3

    ::==========================================================================================================================================================================================

    Example 2
    ::例2

    Using the following diagram, calculate the measures of the remaining three angles.

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    First, state the relationship between 1  and one other angle.
    ::使用下图,计算其余三个角度的度量。首先,说明 1 和另一个角度之间的关系。

    1  and 3  are vertical angles.
    ::1和3是垂直角度。

    Next, use this relationship to calculate the measure of 3 .
    ::接下来,使用此关系来计算 3 的度量 。

    m 1 = m 3

    ::m1=m3

    Next, substitute 40 , for the measure of 1  in the equation.
    ::接下来,换成40 以测量方程式中的11。

    m 1 = m 3 40 = m 3

    ::===================================================================================================================================================================================

    First, state another relationship between 1  and another angle.
    ::首先,说明1和另一个角度之间的另一关系。

    1  and 4  are adjacent angles.
    ::1和4是相邻角度。

    Next, use this relationship to calculate the measure of 4 .
    ::接下来,使用此关系来计算 4 的度量 。

    m 1 + m 4 = 180

    ::m1+m4=180

    Next, substitute 40 , for the measure of 1  in the equation.
    ::接下来,换成40 以测量方程式中的11。

    m 1 + m 4 = 180 40 + m 4 = 180

    ::m1+m4=180404=180

    Next, subtract 40  from both sides of the equation to solve for m 4 .
    ::接下来,从方程的两侧减去40 以解答 m 4 。

    40 + m 4 = 180 40 40 + m 4 = 180 40 m 4 = 140

    ::{\fn黑体\fs22\bord1\shad0\3aHBE\4aH00\fscx67\fscy66\2cHFFFFFF\3cH808080}4... {\fn黑体\fs22\bord1\shad0\3aHBE\4aH00\fscx67\fscy66\2cHFFFFFF\3cH808080}4... {\fn黑体\fs22\bord1\shad0\3aHBE\4aH00\fscx67\fscy66\2cHFFFFFF\3cH808080}4... {\fn黑体\fs22\bord1\shad0\3aHBE\4aH00\fscx67\fscy66\2cHFFFFFF\3cH808080}4... {\fn黑体\fs22\bord1\shad0\3aHBE\4aH00\fscx67\fscy66\2cHFFFFFF\3cH808080}

    First, state the relationship between the remaining angle and one other angle.
    ::首先,说明剩余角与其他角之间的关系。

    4  and 2  are vertical angles.
    ::4和2是垂直角度。

    Next, use this relationship to calculate the measure of 3 .
    ::接下来,使用此关系来计算 3 的度量 。

    m 4 = m 2

    ::m4=m2

    Next, substitute 140 , for the measure of 4  in the equation.

    m 4 = m 2 140 = m 2
     
    ::下一位, 替代 140 , 以测量方程式中的 4 。 m4 = m2140 2 。

    Review
    ::回顾

    Identify whether each angle pair can be classified as adjacent angles or vertical angles or neither.
    ::确定每个角度对是否可划为相邻角度或垂直角度,或两者兼而有之。

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    1. I N K  and  M N L
    ::1. 新加坡和荷兰

    2.  I N J  and  J N K
    ::2. INJ和JNK

    3.  M N L  and  L N K
    ::3. 扎扎扎纳尼和扎扎纳克

    4. J N L  and  I N M  
    ::4. JNL和INM

    5.  I N M and  K N L
    ::5. 曼曼德·卡尼勒

    6. If m I N J = 63  then m M N L = _ .
    ::6. 如果MINJ=63,那么MMNL。

    Use this diagram to answer the following questions.
    ::使用此图表回答下列问题 。

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    7. True or False. 1  and 2  are adjacent angles.
    ::7. 真实或虚假。% 1 和% 2 是相邻角度 。

    8. What is the measure of 1  ?
    ::8. 衡量1的尺度是什么?

    9. What is the measure of 2  ?
    ::9.2的衡量标准是什么?

    10. What is the relationship between 2  and the angle opposite it?
    ::10. 2与与之相反的角度之间的关系是什么?

    11. True or False. Adjacent angles 1 and 2 form a straight line with a value of  180
    ::11. 真实或假。相邻角度1和2形成一条直线,值180____________________________________________________________________________________________________

    Answer true or false for each question.
    ::回答每个问题是否真实或虚假。

    12. Supplementary angles are also vertical angles.
    ::12. 补充角度也是垂直角度。

    13. Vertical angles have the same measure.
    ::13. 垂直角度的测量尺度相同。

    14. Adjacent angles always have a sum of 180 .
    ::14. 近邻角度总有180个。

    15. Adjacent angles are also vertical angles.
    ::15. 近角也是垂直角。

    16. Vertical angles are formed when lines intersect.
    ::16. 当线条交叉时形成垂直角度。

    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 。