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In right △ABC , the right angle is at C, m∠A=30 degrees , and AC=7√5 units.
What is the perimeter of △ABC

 Mar 19, 2020
 #1
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B

 

C    7√5          A

 

We  have  a 30-60-90  right triangle

 

Angle  CBA   = 60°

 

Angle  BCA  = 90°.....the side opposite this has the length   2 ( 7√5) / √3  = 14√5 / √3  = 14√15 / 3

 

Angle  BAC  = 30°  ....the  side opposite this has the length  7√15/3

 

So....the perimeter  = 

 

7√5  +  (√15/3) (14 + 7)  =

 

7√5  + (√15/3)(21)  =

 

7√5  + 7√15  =

 

7 (√5 + √15)  units ≈   42.76  units

 

 

 

cool cool cool

 Mar 19, 2020

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