Hi! When u see the dashes on the triangle, it represents parallel lines which basically means the two percentages on the missing angles are equal! So, we know that a triangle in total should equal 180°, meaning you would have to do 180-102to find the missing angles. Then you would have 78° and you would divide that by two to have each individual angel. 78/2 is 39.
X=39°
Y=39°
