Yes
Yes, it can always be divided in 2 triangles. This is because every quadrilateral has 2 diagonals. It is these diagonals that divide the quadrilateral into 2 triangles.
Not true because all quadrilaterals contain 2 triangles
Yes, any quadrilateral can be divided into two equal triangles by drawing a diagonal between two of its vertices. This diagonal splits the quadrilateral into two triangles, which can have equal areas if the diagonal divides the shape symmetrically. However, not all quadrilaterals will result in two equal-area triangles unless specific conditions are met regarding their dimensions or angles.
You will either get two triangles, two rectangles, or two irregular quadrilaterals.
Polygon
Not at all. All quadrilaterals can be skewed into parallelograms and so are not strong. They need to have a diagonal brace - effectively making two triangles.
No. You can have two triangles that are congruent to one another, and two quadrilaterals that are congruent to one another. But the triangle cannot be similar to the quadrilateral!
They are called polygons
There are two types of quadrilaterals that are formed when two congruent equilateral triangles are joined. These shapes are rhombus and parallelogram.
Two triangles
To join triangles to make quadrilaterals, you can align two triangles along one of their edges, ensuring that the edges match perfectly. By combining the two triangles this way, their adjacent sides form a new quadrilateral. You can also use multiple triangles, ensuring that their edges continue to align to create a closed four-sided shape. Experimenting with different triangle orientations can yield various quadrilateral shapes.
You can divide a quadrilateral up into as many triangles as you want, but at least two.