Which equation represents the value of zero in a triangle when and all other angle information is known

Answer 1

θ is Greek letter theta.

If your question means:

Which equation represents the value θ in a triangle when all other angle information is known?

then

The sum of the angles in a triangle = 180 °

α + β + θ = 180°

Subtract ( α + β ) from both sides of the equation.

θ = 180 ° - ( α + β )