A four-sided shape with one right angle is a quadrilateral. There is no more specific term, unless it has more than one right angle or has equal sides.
a right triangle
cheesse
A right-angle triangle.
2
A right angled triangle.
A right angle triangle
a right triangle
cheesse
A right-angle triangle.
2
no
A square or a rectangle.
any right triangle will have an acute angle in it
A right angled pentagon.
A right angled triangle.
polygon
A Triangle~!