base angle of the isosceles right angled triangle

= (180° - 90°) ÷ 2
= 45°


Notice that this angle is merely folded up and appears at the tip of each end of the flower.

There's another triangle formed. One of its angle is 34°. The other angle , at each tip of the flower is that 45°

So x = 180° - 34° - 45 = 101°


As for y,


Notice that when you fold the paper, the angle it makes is just the mirror image of the angle between the base and the dotted line before folding.


So on each side, the angle between the base and dotted line before folding are both are 34°. Total there are 4 angles of 34°.

Angle y
= angle of straight line - these 4 angles

= 180° - 4 x 34°
= 180° - 136°
= 44°

The diagram is poorly drawn as the corner where angle x is should be flush with the sides of the triangle and not raised above it.