Answer:
B ⊂ A
Step-by-step explanation:
We know that:
A {x|x is a polygon}
So set A is the set of all polygons.
B {x|x is a triangle}
Set B is the set of all triangles.
First, a polygon is a plane geometrical figure made of a finite sequence of straight segments.
For example, a triangle is a polygon, a rectangle is a polygon, etc.
Then, all triangles are polygons, but not all polygons are triangles.
So we can conclude that the whole set B is included in the set A.
Then the correct notation would be:
B ⊂ A
