A right triangle or a rectangle are polygons that have at least one right angle. There are other quadrilaterals and many irregular polygons that could have at lease one right angle, too. Many of them. Note that a polygon is any planar figure constructed of a finite number of line segments to make a closed figure. By that definition, which is a correct one, the triangle and rectangle are polygons. And a quadrilateral (of which the rectangle is special case) can be constructed with just one right angle, though it will be a bit quirky looking. Once we start adding sides to make different polygons, the game is afoot because so many possibilities exist.
acute
triangle?????????
rhombus
Rectangle
There is no specific name, but "right-angled polygon" will suffice.
Any polygon can have just one right angle, from a right angled triangle upwards.
A polygon with 4 or more sides can have more than one right angle.
right-angle triangle has at least one right angle .
Any polygon with more than three sides may have an angle greater than 180 degrees.
There is no specific name, but "right-angled polygon" will suffice.
Any polygon, if it is not regular, can have 1 right angle.
A right angle triangle
The answer to this would be any acute polygon, such as an equilateral triangle. The definition of acute polygons is that no angle in the polygon is greater than or equal to 90 degrees.
right angle triangle
Any polygon can have one right angle, for example, a right angled triangle.
Any polygon can have just one right angle, from a right angled triangle upwards.
There is only one regular polygon which contains right angles - this is a square. None of the other regular polygons from 3 sides and upwards has a right angle.
A right triangle.
A polygon with 4 or more sides can have more than one right angle.
An irregular septagon: the right-angle will prevent it being regular.
right-angle triangle has at least one right angle .