Analysis and Approaches for IBDP Maths Ebook 1 | Page 116

Your Practice Set – Analysis and Approaches for IBDP Mathematics
(b)
The required area
1 2
� (BD) (DBC) ˆ
2
1 2
� (3) ( � � ABC) ˆ
2
(M1) for valid approach
1 (3)
2 � � �
� ��
� �
2 � 3�
(A1) for substitution
2
� 3�
cm
A1 N2
[3]
Exercise 39
1. The following diagram shows a triangle ABC and a sector BDC of a circle with centre
B and radius 9 cm. The points A , B and D are on the same line.
AB � 3 cm , BC � 9 cm , area of triangle
ABC
27 3
cm
4
2
� , ˆ
ABC is obtuse.
(a) Find ˆ ABC .
(b)
Find the exact arc length of the sector BDC.
[5]
[3]
2. The following diagram shows a triangle ABC and a sector BDC of a circle with centre
B and radius 10 cm. The points A , B and D are on the same line.
AB � BC � 10 cm , AC � 10 3 cm , ABC ˆ is obtuse.
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