Which relationship is always correct for the angles p, q, and r of triangle ABC? (1 point)
A triangle ABC has angle ABC labeled as q, angle BCA labeled as r, and the exterior angle at A labeled as p.
p + r = q
p + q + r = 180 degrees
p + q + r = 90 degrees
q + r = p
The correct relationship for the angles p, q, and r of triangle ABC is:
p + q + r = 180 degrees