a triangle
An isoceles triangle.
A triangle.
Any polygon can have 3 equal interior angles, but it doesn't have to.An equilateral triangle always has 3 equal interior angles.
An equilateral triangle.
An octagon
If the shape has 3 angles in all, where two of the angles are acute, then the shape is a scalene triangle.
No polygon can have less than 3 angles. It would be a triangle with 3 sides but that has 3 angles.
A seven sided shape is a heptagon.
Triangle
An isoceles triangle.
a triangle
a pentagon
triangle
3
Triangle
A triangle.
If the question is about a plane shape with exactly 3 right angles it could be an irregular polygon of 5 or more sides. If the shape can have more than 3 right angles then a square or rectangle are also possible. Finally, in 3 or more dimensions, a polyhedron with any number of faces can have 3 or more right angles.