+0  
 
+1
621
4
avatar+1442 

Find the area of triangle ABC if AB = BC = 12 and angle ABC = 120 degrees.

 

If no ones too busy making out today I sure would love some help on this problem!

 Feb 14, 2018
 #1
avatar+405 
+3

Area=1/2absinC

Area=1/2*12*12*sin120

Area=1/2*144*sin120

Area=72*sin120

Area=62.4cm²(1dp)

 

smileysmileysmiley

 Feb 14, 2018
edited by qualitystreet  Feb 14, 2018
edited by qualitystreet  Feb 14, 2018
 #2
avatar+16286 
+2

sin 30 = h/12     h= 6

6^2 + (1/2b)^2) = 12^2

(1/2 b)^2 = 144-36 = 108

b=20.78

 

Area = 1/2 bh = 1/2  20.78  x 6 = 62.35 units^2

 Feb 14, 2018
 #3
avatar+1442 
+3

Thanks so much, both of you!

 Feb 14, 2018
 #4
avatar+405 
+2

no problem any time

 

smileysmileysmiley

qualitystreet  Feb 14, 2018
edited by qualitystreet  Feb 14, 2018

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