Two perpendicular lines
a right angle is a right angle
an angle with a acute and right angle
To trisect a right angle form an equilateral triangle with one vertex at the right angle and then bisect that angle of the equilateral triangle. (It is impossible to trisect a general angle using only compass and straight edge - the right angle is a specific exception.)
No it is impossible for a right triangle to have an obtuse angle therefore it will have one right angle and two acute angles.
The complementary angles form a right angle with the shared ray.
A right angle triangle.
A right angle triangle.
Yes. The square is a special form of the angle notation, which specifies a right angle. It is common to put it there, since it clearly defines that triangle as a right-angled and not just a very close one.
right-angle triangle has at least one right angle .
A right angle only has one angle.
A right-angle is one of 90 degrees.
One half of a right angle is a 45 degree angle.