Explanation: A triangle adds to 180 degrees. All you need to do is subtract 57 from 180 and you should get 123. 123 divided by 2 is 61.5. Now, you should know that it’s 61.5 for for the other two angles because the little line that goes through the triangle on each side indicates that those two sides are congruent. If you want to check just add 61.5 + 61.5 + 57 and you should get 180. Hope this helps. :)
