An obtuse triangle does not always have three congruent sides. An obtuse triangle can be any form that always has three angles.
The three angles of a triangle are always equal to 180°, if not equal to 180° then it is not a triangle.
In a triangle the smallest angle is always opposite the shortest side. It will always be an acute angle.
Never
The sum of the three angles of a triangle is always 180º
They can tesselate - provided they are the correct shapes.
YES.
Yes, every triangle will tessellate.
Yes, any triangle will tessellate.
Yes they do tessellate
Triangle, square, hexagon.
No. Circles lack straight edges, and thus cannot tesselate with triangles.
No only three can tesselate. they are: An equilateral triangle, a square and a 6 sided hexagon.
By themselves, only 3: triangle, square and hexagon. But there are combinations: eg octagon + square.
Yes, all triangles will tesselate. Twiddle your triangle round so one side is horizontal, and it's easier to see then.
Yes, rectangles tesselate. A tessellation is a tiling pattern.
Because angles on a straight line add up to 180 degrees and the 3 interior angles of any triangle add up to 180 degrees. So it follows that all triangles will tessellate.