Angle 5 would be 128° as well, and angle 7 is a vertical angle to 5, also making it 128°.
Angle 6 is 52°, Angle 7 is 128°
Angle 5-8 added together would all be 360°, and we already know two are 128°. 128+128=256°
360-256= 104°. Since were trying to find the two remaining angles that are vertical to each other, they will be vertical and equal. Divide by 2. 104/2 = 52