this is a big one. so, first, we need to find the angle that we have enough information to solve, and that is angle 3. we can solve that because we know angle 4, and they are on the same line. a line is 180 degrees, so we just subtract angle 4 from 180. that way, we find angle 3. angle 3 ends up being 70. we also know that a triangle is 180 degrees total. so, we subtract 70 degrees from the inside, in order to find the other two angles. that leaves us with 110 degrees between the 2 other angles. and, since they are the same, we can just divide 110 by 2. that leaves us with each angle being 55 degrees.
