Trapezoids are special parallelograms. Circles are simple closed curves. All polygons are simple closed curves. Squares and rectangles are parallelograms. Scalene traingles can be equiangular.
Right triangles can be scalene triangles.
A triangle can have two right angles. Space figures are the same as plane figures. All rhombi are squares. Circles are polygons. By definition, isosceles triangles have only 2 congruent sides.