#1**+1 **

Minor Arc AB = (2) 72 = 144°

[ A tangent meeting a chord forms an angle half that of the arc intercepted by the chord ]

Angle C = (1/2) measure of minor arc AB = (1/2) 144 = 72°

[ C is an inscribed angle.....its measure is 1/2 the measure of its intercepted arc

Angle A = 180 - 72 - 54 = 54°

[ The sum of the interior angles of a triangle = 180° ]

So.....triangle ABC is isosceles because angles A and B are equal

CPhill Nov 29, 2018