Answer:- The quadrilateral must be a rhombus.
Explanation:-
Given :-For a craft project, two equilateral triangles are taped together to create a quadrilateral.
We know that an equilateral triangle is a triangle in which all the sides and angles are equal such that its each interior angle should be 60°.
If we join two equilateral triangle by to create a quadrilateral then the sides of the quadrilateral would be same as it was constructed by equilateral triangle.
Then the interior angle for the sides which are not joint will remain same as 60°.
But the interior angle for the vertex of quadrilateral which has formed by joining two triangles will become 60°+60°=120°.
Thus it is not a square , rectangle (no right angle )or trapezoid(quadrilateral have equal sides).
Therefore, the quadrilateral must be a rhombus.
