Question

one exterior angle of a triangle is
$70$
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Answer 1

YOUR QUESTION IS INCOMPLETE

but if the question is two find the 2 opp. interior angles you can use exterior angle property

Answer 2

Answer:

An exterior angle of a triangle is equal to the sum of the opposite interior angles. For more on this see Triangle external angle theorem. If the equivalent angle is taken at each vertex, the exterior angles always add to 360° In fact, this is true for any convex polygon, not just triangles.