three
In Euclidean geometry, 180. Other answers are possible, depending on the surface on which the triangle is drawn.
An isosceles triangle has 3 sides two of which are of equal lengths it also has 3 interior angles two of which are of equal sizes.
There are 3 angles in a triangle
A triangle has 3 angles.
There are 3 angles in a triangle.
A triangle has three internal angles and three external angles, for a total of six angles.
None because a scalene triangle has 3 different side lengths and 3 different interior angles that add up to 180 degrees.
You'd have to know some relationship, formula, equation etc. among the angles and the lengths. There would be many relationships to choose from if the items you mention are the parts of a triangle, but if they are, you've kept it a secret.
An obtuse triangle can have no right angles, and has two equal angles.
3
Every triangle must have at least 2 acute angles, otherwise it is impossible to make the 3 sides connect.
3