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					1.4 –Measure and Classify Angles &
Angle Constructions
Angle: Two different rays with the same initial
       point. Measured in degrees.


                     B


                 1
             A
                         C

          A, BAC, CAB, 1
       Common initial
Vertex point, where                   pt. A
       rays meet
                         vertex


                        side
                                      AB
        The rays of
Sides
        the angle
                                      AC
                               side
           Point               Pt. D is in
                           D
Interior   inside an           the interior
Point      angle               of BAC



         Point                 Pt. E is in
Exterior outside an            the exterior
Point    angle                 of BAC
                       E
           Angle more
Acute      than 0°, but                 mA = 50°
           less than 90°    A
           Angle that
Right      measures 90°
                                        mR = 90°
                                R
           Angle more
Obtuse     than 90°, but                mO = 110°
           less than 180°
                                O

           Angle that                   mS = 180°
Straight
           measures 180°            S
Angle Bisector: Ray that cuts an angle in half to
                make 2 congruent angles

     P                         QS bisects PQR
              S
                                PQS  SQR
                              mPQS = mSQR
 Q           R
  Note: To name an angle use “  ”, but when

  stating its measure use “_______”.
                              m
Adjacent angles: Two angles that share a
                 common side and vertex




                        2 1



               1 is adjacent to 2
Angle Addition Postulate:
If you add two adjacent angles, it totals to get
their sum.

                         A       C

                             B       D


      mABC + mCBD = mABD
1. Give three names for the angle shown, then name the
vertex and sides.
                           Names      Vertex    Sides

                           DEF        Pt. E     ED
                           FED
                                                 EF
                           E
1. Give three names for the angle shown, then name the
vertex and sides.
                           Names      Vertex    Sides

                            QVS                 VQ
                                       Pt. V
                            SVQ
                                                 VS
                            V
2. Classify the angle as acute, right, obtuse or straight.


mA = 115°



                         obtuse
2. Classify the angle as acute, right, obtuse or straight.


mA = 90°



                          right
2. Classify the angle as acute, right, obtuse or straight.


mA = 85°



                          acute
2. Classify the angle as acute, right, obtuse or straight.


mA = 180°



                         straight
3. Use a protractor to find the measure of the angle to
the nearest degree. Then classify the angle as acute,
obtuse, straight, or right.




              91°        obtuse
3. Use a protractor to find the measure of the angle to
the nearest degree. Then classify the angle as acute,
obtuse, straight, or right.




              32°        acute
3. Use a protractor to find the measure of the angle to
the nearest degree. Then classify the angle as acute,
obtuse, straight, or right.




              180°       straight
4. Find the indicated measure.



                          mPRS = 81+42
                          mPRS = 123°
4. Find the indicated measure.



                          mWXZ = 90 – 26 =
                          mWXZ = 64°
mNRP + mPRQ = mNRQ
   8x + 7 + 4x – 1 = 78
          12x + 6 = 78
              12x = 72
                 x=6

       mPRQ = 4(6) – 1
       mPRQ = 24 – 1
       mPRQ = 23°
mADB + mBDC = mADC
  11x – 7 + 5x – 3 = 118
         16x – 10 = 118
              16x = 128
                 x=8

       mADB = 11(8) – 7
       mADB = 88 – 7
       mADB = 81°
6. Find each indicated angle.



                        15°
              90°

            75°               90°

                  15°
Find each indicated angle.


                                    67°
     106°
     74°
                                  157°


   a = 180-74 = 106°     c = 180-90-23 = 67°
   b = 180-106 = 74°     d = 180-23 = 157°
                           5x + 2 = 7x – 6
                                2 = 2x – 6
                                 8 = 2x
                                 4=x



mABC = 5(4)+2 + 7(4)-6 = 20+2 +28-6 = 44°
                            5x + 13 = 9x – 23
                                 13 = 4x – 23
                                 36 = 4x
                                  9=x



mABC = 5(9)+13 + 9(9)-23 = 45+13+81-23 = 116°
                          HW Problem
Section   Page #                   Assignment                Spiral ?s

 1.4      28-32    4-14 even, 21, 23-27 odd, 33-38, 40, 41   9-11
                                # 38




                                                                 53°
                                                               37°

       **Bring compass and ruler tomorrow!
         Books will not be needed

				
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posted:6/8/2011
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