a right angle triangle.
A right (angled) triangle.
A right triangle has three sides and one right angle.
A right angle triangle
A right triangle has an acute and right angle.
A right angle triangle. (if it is a triangle)
A right angle triangle
A right angle triangle
a 3 sided shape is a right angle triangle
a right angle triangle.
a right triangle
A triangle can have a right angle, but it isn't regular if it does. Rectangles aren't regular, but have four right angles. Squares are regular quadrilaterals, and have four right angles. No other regular polygon has any right angles.
right angled triangle
A right (angled) triangle.
A right angle triangle.
An obtuse triangle.