Which relationship is always true for the angles r, x, y, and z of triangle abc?
x + z = y
180 degrees − x = r
x + y + z = 180 degrees
x + y + z = 90 degrees

Answer with explanation:

In the problem , given about triangle, four angles are given , r,x ,y and z.

→→One of the three, must be exterior angle of triangle ABC, and other three, must be interior angles of Δ ABC.

So, two properties of triangle that we will use in this problem

1. Angle sum property of triangle: the sum of three angles of triangle is 180°.

2.Exterior angle property: Exterior angle of a triangle is equal to sum of two interior opposite angles.

So, if x, y and z are interior angles , and r is exterior angle

then

Option 3: x + y + z = 180° is always true.

either, r= y + z

and ,r +x=180°