Question

If two equilateral triangles are drawn such that they have a common side, then the quadrilateral formed is a __

Answer 1

If I join 2 equilateral triangles, I get a quadrilateral with all sides equal. Since the angle of an equilateral triangle is ${60}^{\circ }$, no sides will be perpendicular. The quadrilateral formed cannot be a square. Hence, it is a rhombus.