Exterior Angles

Solve mathematical problems involving exterior angles (easy)

Find the value of the exterior angle of each triangle.

\(m \angle EBD = ?,\) \(m \angle C = 97^\circ,\) \(m \angle D = 30^\circ\)

Use informal arguments to establish facts about the angle sum and exterior angle of triangles, about the angles created when parallel lines are cut by a transversal, and the angle-angle criterion for similarity of triangles. For example, arrange three copies of the same triangle so that the sum of the three angles appears to form a line, and give an argument in terms of transversals why this is so.