True. An obtuse angle is between 90 and 180 degrees.
True
In Euclidean geometry, a triangle must be one of these: acute, obtuse, or right. Maybe there is a non-Euclideangeometry for which some obtuse triangles can contain a right angle, but it doesn't happen in Euclidean geometry.
No
true
True. An obtuse angle is between 90 and 180 degrees.
False
True
Yes
In Euclidean geometry, a triangle must be one of these: acute, obtuse, or right. Maybe there is a non-Euclideangeometry for which some obtuse triangles can contain a right angle, but it doesn't happen in Euclidean geometry.
No
False
Yes but anything over 90 degrees is an obtuse angle
True and all 3 angles must add up to 180 degrees.
true
It is true
true