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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

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 A12



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