This puzzle looks simple at first, but there is one important detail that can easily be missed.
The figure shows a right angle at the bottom-left corner.
It also shows a 130° angle at the top-right corner.
There are matching double tick marks on the vertical and horizontal sides, which means those two sides are supposed to be equal in length.
So let’s work through the information carefully instead of relying only on how the drawing looks.
First, look at the 130° angle.
That angle is an exterior angle of the triangle.
The interior angle next to it must add up to 180° with the 130° angle.
So the interior angle at the top-right is:
180° − 130° = 50°
Now we know two angles of the triangle.
The angle at the bottom-left is marked as a right angle, so it is:
90°
Using the angle sum of a triangle, the remaining angle would have to be:
180° − 90° − 50° = 40°
That would make x = 40° if we use only the angle markings.
But there is an important problem.
The two sides marked with the same double ticks are supposed to be equal.
Those two sides meet at the 90° angle.
That means the triangle is supposed to be an isosceles right triangle.
In an isosceles triangle, equal sides have equal opposite angles.
Therefore, the two angles opposite those equal sides must be equal.
Since one of the angles is already 90°, the other two angles must share the remaining 90° equally.
So each of the two smaller angles would have to be:
90° ÷ 2 = 45°
That means the top-right interior angle should be 45°.
If the interior angle is 45°, its exterior angle would be:
180° − 45° = 135°
But the picture gives 130°, not 135°.
So the information in the diagram does not agree.
If we use the 130° angle and the 90° angle, we get:
x = 40°
If we use the right angle and the equal-side markings, we get:
x = 45°
Both cannot be true at the same time.
Therefore, there is no single mathematically consistent value of x for the diagram as drawn.
The puzzle appears to contain an error in either the 130° label or the equal-side markings.
If the intended puzzle ignores the equal-side markings, then the expected answer is 40°.
But if all the markings are meant to be valid, the triangle is impossible as shown.
Final Answer: 40° — only if the 130° and 90° angles are the intended information.
Strictly using every marking in the image, however, the diagram is inconsistent and has no valid solution.
