A famous math puzzle on a wall has caught everyone’s attention online.
It looks like a simple geometry test for fifth-grade students.
However, many adults are getting the wrong answer because they rush.
Let us look closely at the diagram and solve it step by step.
The puzzle shows a triangle with two extended straight lines at the top.
Inside the triangle, we see an angle labeled as 50°.
There is also an unknown angle labeled as n.
Above the top vertex, between the extended lines, we see another unknown angle labeled as m.
We are asked to find the values of both m and n.
First, look at the two small hash marks on the sides of the triangle.
In geometry, these marks mean that the two sides are equal in length.
A triangle with two equal sides is called an isosceles triangle.
An isosceles triangle always has equal angles opposite those equal sides.
This means the two base angles at the bottom must be equal.
Since the bottom-left angle is 50°, the bottom-right angle n must also be 50°.
Now we have found our first answer easily: n = 50°.
Next, we need to find the value of angle m.
To do this, we first need to find the top interior angle of the triangle.
We know that the sum of all three angles inside any triangle is always 180°.
We already know two of the angles are 50° and 50°.
Adding them together gives 50° + 50° = 100°.
Subtracting this from 180° leaves us with 180° – 100° = 80°.
So, the top interior angle inside the triangle is 80°.
Now, look at how the lines cross at the top vertex to form angle m.
The lines form two opposite angles where they intersect.
In geometry, these are called vertical angles (or vertically opposite angles).
Vertical angles are always equal to each other.
Since the top interior angle is 80°, the opposite angle m must also be 80°.
By following simple logic and basic rules, the puzzle is solved.
The correct answers are:
m = 80°
n = 50°
