Analysis and Approaches for IBDP Maths Ebook 1 | Page 122

Your Practice Set – Analysis and Approaches for IBDP Mathematics
41
Paper 2 Section A – Areas and perimeters of sectors
Example
The following diagram shows a circle with centre O and radius 100 cm.
The points A , B and C are on the circumference of the circle and
(a) Find the length of arc ABC .
(b) Find the perimeter of sector OABC .
(c) Find the area of sector OABC .
AOC ˆ � 1.5 radians .
[2]
[2]
[2]
Solution
(a)
(b)
(c)
The length of arc ABC
� (100)(1.5)
(A1) for substitution
� 150 cm
A1 N2
The perimeter of sector OABC
�150 �100 � 100
(M1) for valid approach
� 350 cm
A1 N2
The area of sector OABC
1 (100)
2
� (1.5)
2
(A1) for substitution
2
� 7500 cm
A1 N2
[2]
[2]
[2]
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