Oh, what a happy little question! In a star shape, each point creates an angle. If we connect those points, we can see that each angle is less than 90 degrees, so there are no obtuse angles in a star. Just think of all those lovely acute angles coming together to make a beautiful star!
A rhombus have 2 obtuse angles
There are 3 obtuse angles in a heptagon.
A regular star with n points has 2 interior angles of which n are acute and n are reflex.
One and the two others are acute angles
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.