A right triangle has three sides and one right angle.
A square or a rectangle.
no
An irregular pentagon.
Right triangle
A right triangle has three sides and one right angle.
A right-angle triangle.
A right angled triangle.
A square or a rectangle.
a ploygon or quadrilateral
no
A rhombus.
a trapezoid
Rhombus, trapezoid, parallelogram
triangle
an "irregular pentagon"
trapezoid