This activity is about finding the angles in a quadrilateral, which always add up to 360°.
To find angle x, we add up the existing angles and subtract this from 360°.
We can see that the quadrilateral above has two right angles and a third angle of 34°.
90 + 90 + 34 = 214
x = 360 - 214 = 146°
Does that make sense?
Let's have a go at some questions.