Can someone show all the steps? Medal + fan

My teacher wants me to show all steps and I dont even remember what I did. LOL thank you!

a=b=c
c^2 = a^2 + b^2 - 2ab cos(t)
a^2 = a^2 + a^2 - 2a^2 cos(t)
a^2 = 2a^2 - 2a^2 cos(t)
1 = 2[1 - cos(t)]
cos(t) = 1/2
t=60

Question

Can someone show all the steps? Medal + fan



My teacher wants me to show all steps and I dont even remember what I did. LOL thank you!

a=b=c
c^2 = a^2 + b^2 - 2ab cos(t)
a^2 = a^2 + a^2 - 2a^2 cos(t) 
a^2 = 2a^2 - 2a^2 cos(t) 
1 = 2[1 - cos(t)] 
cos(t) = 1/2 
t=60

anonymous · Answer

do you know? @lol2214

anonymous · Answer

I'm trying to figure it out if I do, I'll post

anonymous · Answer

ok thank you so much (:

anonymous · Answer

Okay, so what exactly is it your teacher wants to know? Is this what you did above or is that the problem? Just the steps?

anonymous · Answer

My teacher asked to show how I got 60 as my answer and to show all my steps

anonymous · Answer

The law of cosines says 

 c^2 = a^2 + b^2 - 2ab cos(t) 

 In an equilateral triangle, a=b=c 

 a^2 = a^2 + a^2 - 2a^2 cos(t) 
 a^2 = 2a^2 - 2a^2 cos(t) 
 1 = 2[1 - cos(t)] 

 cos(t) = 1/2 

 And t = 60 degrees when cos(t) = 1/2

anonymous · Answer

is that what i should tell her? @lol2214

anonymous · Answer

I'm pretty sure the link I sent you may help you decide from what your teacher is looking for.