Thread: Triangle with angle of 60 degrees

Hello all.
I have a problem : Proof that triangle has an 60⁰ angle if and only if
Please help, no idea

Hey darence.

First off, we know that all angles equal 180 degrees or pi radians.

Now y = pi - b - pi/3 so prove that sin(3*pi/3) + sin(3*b) + sin(3*(2pi/3 - b) = 0 and you're done.

Give me explanation. I dont understand

Basically I set one angle to 60 degrees (or pi/3 radians) and the rest add up 180 degrees (or pi radians).

Then you just show that the equation holds and then you're done.