Sides KM and FH in the triangles below will be placed together to form a quadrilateral.
Which best describes the quadrilateral that will be formed?
parallelogram
rectangle
rhombus
trapezoid

Any polygon that has exactly 3 sides is called a triangle. Here you haven't provided any figure, so I'll assume that we have two triangles as indicated in the figure below. As you can see, we have two sides:

When placing together we realize that those sides measures the same, so:

So is the diagonal of the shape. From the figure we also know that opposite sides are equal and parallel, therefore, this shape represents a parallelogram. Remember that a parallelogram is a quadrilateral where both pairs of opposite sides are parallel.

So correct option is:

Parallelogram

okay wait before i answer, is this for your points on a graph?

practice. practice. practice.