Use a protractor.
to measure a shape
An angle in a four sided shape can have any measure in the interval (0, 360) degrees except 180 degrees.
A right angle triangle.
The measure of an exterior angle depends on the shape.
|\ |_\ right-angled triangle
Not necessarily. But a regular triangle must be acute angled.
Octagon
Yes
A square and a rectangle have each of their angles as 90°. However, no polygon or shape (unless it is not closed) can have a total angle sum of 90°
A shape in which all angles measure equally is equiangular. Have a good day! :)
The interior angles of a 24 sided shape add up to 3960 degrees
It all matters what the inside angles measure up to. If the inside angles measure up to 360 degrees, the shape will tile. If the inside angles do not add up to 360 degrees, the shape won't tile.