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                                                                           Mathematics  Form 3  Chapter 5 Trigonometric Ratio     Mathematics  Form 3  Chapter 5 Trigonometric Ratio
                                          4                                                                                             3
                       9.  (a)  cos ∠BAC =                                     PT3 Standard Practice  5                       4.   sin x =                                      2.  (a)       AB
                                          5                                                                                             5                                              sin x =   AC             ✓
                              AB = 4 cm, AC = 5 cm                     Section A / Bahagian A                                         3   =   3
                                             2
                              AD = AC  + CD                                      3                                              AC    5                                              cos x/ kos x =   BC      ✓
                                       2
                                                                         1.   cos x =                                                AC = 5 cm                                                      AC
                                 = 5  + 12 2                                     5
                                      2
                                 = 13 cm                                     NP    3                                              tan y = 1.6                                                  AB
                                                                                 =                                                                                                     tan x =                  ✓
                                          12                                 10    5                                               CD                                                          BC
                              cos ∠ADC =                                           3                                                   = 1.6
                                          13                                 NP =    × 10                                          5
                                                                                   5
                         (b)  (i)    tan x = tan ∠DAE                        NP = 6 cm                                               CD = 8 cm                                    (b)   tan x = 0.4 –1
                                      CE   =   4                                                                                 Answer: B                                                x = tan  0.4
                                      BC   3                               NK = 2 × 6 cm                                                                                                   = 21.8°
                                       4  =   DE + 7                           = 12 cm
                                       3      12                                                                              5.  Answer: A
                                                                                        2
                                                                                    2
                                  DE + 7 = 16                              NL = 10  – 6                                                                                     Section C / Bahagian C
                                      DE = 9 cm                                = 8 cm
                                                                                   NL                                         6.  Angle between the line  BK and the Plane      1.  (a)  (i)  ∠PMQ
                                           4                                tan y =
                              (ii)  x = tan                                        NK                                            ADK = ∠BKA                                             (ii)  ∠PLQ
                                         –1
                                           3                                      8
                                    = 53.13°                                   =                                                 AK =  AD  + DK
                                                                                                                                                 2
                                                                                                                                           2
                                                                                 12                                                                                                                8
                                                                                  2                                                 = 24  + 7                                   (b)  (i)  cos x =
                                                                                                                                         2
                                                                                                                                              2
                                      3                                        =                                                                                                                  17
                         (c)  cos x  =                                            3                                                 = 25 cm                                                 NL     8
                                      5                                                                                                                                                          =
                                AB   =   3                                  Answer: C                                                        10                                            76.5    17
                                30    5                                                                                          tan ∠BKA =   25                                           NL = 36 cm
                                      3                                  2.  Assume the length of sides  AB and  BC is
                                AB  =    × 30 = 18 cm                                                                                             10
                                      5                                    2 cm and AD is the height of the equilateral             ∠BKA = tan  –1                                  (ii)  tan y = 1
                                                                                                                                                  25
                                         2
                                BD  = 30  – 18                           triangle.                                        	 		    ∠BKA = 21.8°                                             NL  = 1
                                              2
                                   = 24 cm                                                                                                                                                   LM
                                                                                   2
                                      DC                                    AD = 2  – 1 2                                      Answer: D                                                   36
                              tan y  =                                                                                                                                                           = 1
                                      BD                                       =                                                                                                           LM
                                                                                 3
                                      10                                                                                                                                                     LM = 36 cm
                                   =                                                AD
                                      24                                    sin 60° =                                       Section B                                                              36
                                          10                                        AB                                                                                                     tan z =
                                 y  = tan –1                                                                                                                                                       36
                                                                                      3
                                          24                                                                                                                       1
                                                                                  =                                           1.  (a)   tan 45°                                                z = tan  1
                                                                                                                                                                                                     –1
                                   = 22.62°                                          2                                                                             	                        z = 45°
                                                                                                                                                                     2
                                                                            Answer: B
                                                                                                                                 (b)   sin 60°                       1
                                                                         3.  SW = UW = 8 cm                                                                          2
                                                                                  UW      8                                           cos 60°
                                                                             sin x =    =                                                                          
                                                                                                                                                                     3
                                                                                  VW     17                                      (c)   kos 60°                       2
                                                                                       8
                                                                               x = sin –1  
                                                                                       17
                                                                                                                                 (d)   sin 45°                       1
                                                                                 x = 28.07°
                                                                            Answer: D

                                                                   21                          © Penerbitan Pelangi Sdn. Bhd.  © Penerbitan Pelangi Sdn. Bhd.             22

                                                                                                                     A12



                BOOKLET ANS MATH F3.indd   12                                                                                                                                                                    03/01/2020   10:20 AM
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