Question

I have no idea how to do this problem can you guys shed some light?

Sqrt[7]^2 == r^2 + r^2 - 2 * r * r * Cos[2 * Pi / 3]

Answer 1

i think this is easier look at the problem:(7√)2=r2+r2−2rrcos(2π3)

Answer 2

r^2(1-2cos[2pi/3] = sqrt 49
r * sqrt(1-2cos[2pi/3] ) = 49
r = 49/sqrt(1-2cos[2pi/3] )
r = 49/sqrt(2)

Answer 3

o wait

yeah can't really tell from how you wrote it
you should put these in the equation editor

Answer 4

same concept tho... not sqrt 49... would come out to just 7 instead