In general, such a point is a WATERSHED. In North America, the continental watershed is known as THE GREAT DIVIDE.
A watershed.
A parallelogram. Opposite sides are parallel and congruent.parallelogram is a quadrilateral with two sets of parallel sides. The opposite sides of a parallelogram are of equal length, and the opposite angles of a parallelogram are congruent. The three-dimensional counterpart of a parallelogram is a parallelepiped.Parallelogram - A quadrilateral whose opposite sides are parallel
Never, there are no true "opposite sides" on a triangle as each side intersects the other two at a point. Were two of the lines parallel, the triangle would be missing a point and would not be a closed shape.
The area you are referring to is called a watershed or a divide. It is a boundary separating the flow of rivers towards different sides of a continent. The size of the watershed can vary depending on the topography and geography of the region.
paramid
They are the sides facing each other at opposite sides.
rectangle
Opposite sides are parallel.Opposite sides are congruent.Opposite angles are congruent.
The point equidistant from the three sides of a triangle is the center of the triangle. The center of the triangle is the point of intersection of the medians of the triangle. The medians of a triangle are the line segments that join the vertices of the triangle to the midpoints of the opposite sides.
The opposite sides of a parallelogram are parallel
A heptagon has seven sides so there are no pairs of opposite sides.
Parallelogram opposite sides are congruent opposite sides parallel