Analysis and Approaches for IBDP Maths Ebook 1 | Page 134

Your Practice Set – Analysis and Approaches for IBDP Mathematics
(c)
2 2 2
ˆ OA �OC �AC
cos AOC � (M1) for cosine rule
2(OA)(OC)
2 2 2
ˆ 12 �12 �22.82660156
cos AOC �
2(12)(12)
(A1) for substitution
AOC ˆ � 2.513609997
(A1) for correct value
reflex AOC ˆ
�2�
� 2.513609997
(M1) for valid approach
� 3.76957531
The length of arc ABC
� (12)(3.76957531)
A1
� 45.23490372
� 45.2 cm
A1 N4
[6]
Exercise 44
1. Consider a circle with centre O and radius 14 cm. Triangle ABC is drawn such that its
vertices are on the circumference of the circle.
AB � 20.8 cm , AC � 26.6 cm and ABC ˆ � 1.25 radians.
(a) Find ˆ ACB.
(b) Find BC .
(c) Hence or otherwise, find the area of sector OBAC .
[3]
[5]
[6]
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