( iii ) The area of the triangle ABC 1
� �
� CA � CB
( M1 ) for valid approach 2 1
� ( � 4 i � 8 j� 6 k ) � ( 4 i � 2 j�k )
2 �( 8 )( �1 ) � ( �6 )( �2 ) �
1 � �
� ( 6 )( 4 ) ( 4 )( 1 ) 2 � � � � � ( �4 )( �2 ) � ( 8 )( 4 ) � �
�
1 � � 20 i � 28 j� 24 k
2 1 ( 20 )
2 ( 28 )
2 ( 24 )
2
� � � � � � A1
2 � 20.97617696 � 21.0
A1
( d ) The vector equation of the line L
3
:
� �7 � � �20� � � � � r � �15 � u �28 A2
� �2 � � �24� � � � �
[ 5 ]
[ 2 ]
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