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avatar+188 

2. the diagram shows a sector OAB of a circle with centre O and radius 5cm. the angle between the radii OA and OB is θ radians. the length of the arc AB is 4cm 

a) find the value of θ

b) find the area of the sector OAB

 Aug 15, 2019
 #1
avatar+104688 
+1

No diagram shown....but we  can still figure it  out

 

(a)

 

r  = 5        AB  =  4

 

arc length  =     r*θ

 

So

 

4   = 5*θ    ⇒   θ   = 4/5  (rads)

 

(b)

Area of  a sector  =   (1/2) r^2 θ   =  (1/2) (5)^2 (4/5)  =  [ 25 * 4 ] / 10 =  100 / 10   = 10 cm^2

 

 

cool cool cool

 Aug 15, 2019

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