The equation for the size of an interior angle of an n-sided regular polygon is (n-2)180/n. When n=7, the interior angle of a regular sided shape would be 5x180/7 or approximately 128.57. The polygon in the question has an interior right angle (90 degree angle) and thus cannot be a regular shape. A 7 sided shape is called a heptagon. Thus, the shape described in the question is an irregular heptagon.
There are lots of polygons like that. If by 1 right angle, you mean exactly 1 right angle, there are no such quadrilaterals, but there are pentagons (in fact n-gons for all n>=5.)
a square...
A Square
Not necessarily. A triangle with two equal sides is called an isoceles triangle. A right triangle has one angle that measures 90 degrees.
Square.
A right scalene triangle.
Any polygon can have a right angle. A right angled triangle is an example.
Any polygon, if it is not regular, can have 1 right angle.
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.
A right angle triangle
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a rhombus, a quadrilateral without right angle, a quadrilateral with equal opposite parallel sides but no right angles
Any polygon with 4 or more sides can always have a right angle.
It can but need not.
It is a right angle triangle
A right trapezoid.