I know, my brother is mathematically gifted and I would constantly annoy him doing things like this.
I also had a bad maths teacher which killed any interest I had in maths (even though I use vectors every day).
Fact is a kite shape must add up to 360 degrees, that’s how it is for a 4 sided polygon anyways. But the diagram is misleading (probably deliberate) and there’s not really a question.
I think that’s inherently restricted by the problem? (Even for the 8x shown in the graphic, which isn’t all of the angles, x has to be less than 45 degrees.)
I can’t really read the number though… so you are assuming that the interior angle is 90 degrees? That’s the only way it can work if they are all equal.
Internal angles of a triangle must add up to 180 degrees. Triangle ABD must be an equilateral triangle as angles A and D are the same sizes ( A is X+2X = 3X, angle D is also 3X, Angle B must therefore be 3X) so each interior angle is sixty, making X 15 degrees.
If there were any reason to think it is an equilateral triangle (which there isn’t), you’d be correct that each angle would be 3x and total 60*. Which would put x=20.