How do you find the exact value of the third side given triangle ABC, b=4, c=4, and #mangleA=pi/3#?

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Answer 1 · 2017-02-07T06:25:41

Applying the Cosine Rule , #a^2=b^2+c^2-2bc cosA#

#=16+16-2(4)(4)cos(pi/3)=16+16-2(4)(4)(1/2)#

#=16+16-16=16#.

#:. a=4#.

Alternatively , in #DeltaABC, b=c rArr m/_B=m/_C, &, m/_A=pi/3#

# rArr m/_B=m/_C=m/_A=pi/3 rArr Delta ABC is" equilateral."#

#:.a=b=c=4.#