Here's a list of shapes that need a right angle:
square
rectangle
right triangle
It has to be 90 degrees to be a right angle.
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.
An equilateral triangle on on of the arms of the right angle.
Because the phrase 'right angle' indicates 90 degrees whereas there is no such angle as a 'left angle'
A shape that has 2 right angles, 1 acute angle, and 2 obtuse angles is a quadrilateral. One possible example is a right trapezoid, where two angles are right angles, one angle is acute, and the last angle is obtuse. This combination of angles can create various quadrilateral shapes, but they must maintain the sum of interior angles equal to 360 degrees.
It has to be 90 degrees to be a right angle.
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.
It could be a right angle or a reflex angle
That it must be a right angle triangle because the 3rd angle must be 90 degrees
An equilateral triangle on on of the arms of the right angle.
triangle
A right angle triangle must have a 90 degree angle and two acute angles.
Because the phrase 'right angle' indicates 90 degrees whereas there is no such angle as a 'left angle'
A shape that has 2 right angles, 1 acute angle, and 2 obtuse angles is a quadrilateral. One possible example is a right trapezoid, where two angles are right angles, one angle is acute, and the last angle is obtuse. This combination of angles can create various quadrilateral shapes, but they must maintain the sum of interior angles equal to 360 degrees.
Acute triangles. They can have three angles, all less than 90 degrees (total is 180 degrees).Shapes with more than three sides must have angles of 90 degrees or more because the total of their angles must be 360 degrees (quadrilaterals) or more.
A right-angle triangle must have one corner of 90 degrees.
One angle must be 90o, which is the right angle. The sum of the other two angles must equal 90o.