An acute triangle.
Any polygon can contain acute interior angles.
An acute polygon is one whose interior angles are all acute. Only a triangle can be an acute polygon.
A polygon, that is, a plane area bounded by any number (>2) of straight lines can have acute angles.
A regular pentagon has no acute angles. It is possible to draw a pentagon (five sided polygon) where four of the internal angles are acute.
An acute triangle.
If its acute angles are different then it is not a regular polygon but if it has 3 equal acute angles of 60 degrees then it is a regular equilateral triangle
The only polygon with just acute angles is an acute angled triangle.
Any polygon can contain acute interior angles.
An acute polygon is one whose interior angles are all acute. Only a triangle can be an acute polygon.
That's an 'acute' triangle.
Parallelogram.
A triangle having all angles less than 90 degrees is a polygon having no parallel sides and all acute angles.
A square
A polygon, that is, a plane area bounded by any number (>2) of straight lines can have acute angles.
A triangle.
A right angle triangle