This is an isosceles triangle. How do we know? Well, the two little bar they put means that it is isosceles. When you add all the angles together, you MUST find them equal to 180. Another you need to keep in mind is that the angle that are face to face with each other are ALWAYS equal.
Too much talking...we gonna solve the problem.
x + x + 72 = 180 2x + 72 = 180 2x = 180 - 72 2x = 108 x = 108/2 x= 54 That's the answer .
--------------------- What did we say earlier? We said that when we add all the angles together we MUST find them equal to 180. So, we gonna replace x by 54
54 + 54 + 72 = 180 180 = 180 So.. yes we got it right!