right angle triangle
A right triangle.
If it has no right angle then a scalene triangle would fit the given description
a rhombus, a quadrilateral without right angle, a quadrilateral with equal opposite parallel sides but no right angles
It is the right angle triangle which has 3 sides whereas all quadrilaterals have 4 sides.
A rectangle has four sides whereas a right angle triangle has only three sides.
A right triangle.
If it has no right angle then a scalene triangle would fit the given description
a rhombus, a quadrilateral without right angle, a quadrilateral with equal opposite parallel sides but no right angles
It is the right angle triangle which has 3 sides whereas all quadrilaterals have 4 sides.
It could be an isosceles right triangle, or it could be a non-regular specimen of any polygon with more than three sides.
A rectangle has four sides whereas a right angle triangle has only three sides.
If this makes sense.... something like this |\ | \ |___\ A three sided polygon that has one right (90 degree) angle and all three sides have different lengths
There are three sides.
A polygon with 3 vertices and 3 sides is known as a triangle. If it has one right angle, it is specifically a right triangle. In a right triangle, one of the angles measures 90 degrees, and the other two angles are acute, adding up to 90 degrees to complete the total of 180 degrees for all three angles.
A right angle triangle
Any polygon with more than three sides may have an angle greater than 180 degrees.
Five side is always a pentagon, but there's no pentagon that always has exactly one right angle. A regular pentagon has no right angles. An irregular pentagon can have one, two, or three right angles, or none.