Equilateral and Isosceles Triangles
Hexagon
Yes the interior angles of a regular octagon are obtuse.
No, not if it is a randomly-drawn 8-vertex shape. Octagons only have all- obtuse angles if it is a regular octagon, like the shape of a stop sign.
2 obtuse and 2 acute in the classic kite shape.
this shape would be a rhombus
An octahedron is a closed 3-d shape with 8 polygonal faces. There are 257 topologically different convex octahedra. In addition there are concave octahedra. Some of these will have no obtuse angles, others will have several.
It depends on they type of arrowhead you have. If it is a arrowhead in the shape of a directional arrow, there are no obtuse angles. The most possible obtuse angles is 1.
There is no three-sided shape with two obtuse angles, because the three interior angles of a three-sided shape, which is a triangle, add up to 180 degrees, and two obtuse angles would be over 180 degrees.
a pentagon
None.
None.
supplementary angles