Answer:
angle 1: 51 angle 3: 123, angle 2: 18, angle 4: 39
Explanation:
First lets find angle 1: We can see that the triangle already has 2 angles filled in, so remember that triangles are 180 degrees total. Now we take 72+57=129 degrees. Now 180-129=51 degrees that were missing.
Angle 3: angle 57 and angle 3 will add up to 180 degrees, because it is a line. So all we need to do is subtract 180-57=123 degrees.
Angle 2: We see that there is a right angle on that corner, so we already have 72 degrees. Take 90-72= 18 degrees.
Angle 4: We know angles 3 and 2, so add them up: 123+18=141. Triangles add up to 180 degrees, so 180-141=39 degrees for the missing angle.