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https://vle.mathswatch.co.uk/images/questions/question15776.png

 

 

winkwinkwink

lynx7  Feb 27, 2018
edited by lynx7  Feb 27, 2018
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 #1
avatar+86565 
+2

We need to find PQ

 

PQ   =  sqrt ( 3^2 + 5^2  - 2(3)(5)cos (81) ) ≈  5.4136

 

So to calculate angle PBQ  we have that

 

arccos [ ( (5.4136)^2 - 9^2 - 9^2 ) / (-2 *81) ]  ≈ 35°

 

So the area of the sector is

 

3.142 * (9)^2 (35/360)  =

 

3.142 * 81  *  (7/72) ≈  24.74 cm^2

 

 

 

cool cool cool

CPhill  Feb 27, 2018
edited by CPhill  Feb 28, 2018

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