Answer :
Yes, all angles of a triangle less than 90 is a acute triangle.
Acute Triangles
A triangle is a basic polygon with three sides and three vertices. Since it has three sides, it has three interior angles.
An acute triangle is a type of triangle in which all the three internal angles of the triangle are acute. Acute triangles are also called acute-angled triangles. Even though the length of the sides of acute triangles differs, the interior angles are never more than 90°.
The sum of angles of a triangle must sum to 180°.
Learn more about Acute Triangles and polygons here :-
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