A plane (flat) shape with three sides is called a "triangle".Notice that if it has three sides, then it must have three angles.
An equilateral triangle
scalene triangle
It doesn't have to, but it can. A trapezoid is any shape in which there is a pair of parallel sides. This means that a square can be classified as a trapezoid. But notice that a four-sided shape can never have ONLY three 90° angles. The sum of angles of a four-sided shape is 360--this means that if you have three 90° angles, then the remaining angle must be 360-3(90) which is 90°, giving you four right angles. * * * * * No you cannot. As indicated in the second paragraph of the above answer, three right angles implies that all four angles are right angles and that makes the figure a rectangle (or a square).
A scalene triangle is a triangle in which there are no sides or angles with the same measures.
The following shape has three sides and the only angles are right angles. ----- | |___
An irregular hexagon.
A triangle is a shape with three sides and three angles. This is a very basic shape taught to young children.
Any shape with three sides and three angles is called a triangle.
A plane (flat) shape with three sides is called a "triangle".Notice that if it has three sides, then it must have three angles.
Isosceles triangle.
An equilateral triangle has three equal sides and three equal angles.
I will rephrase your question as "What shape has only three right angles?" A shape is a 2D drawing that encloses some space. The sum of the angles must exceed 270 degrees. A rectangle is out of the question as it has four right angles. But a 5 sided shape with unequal sides (irregular pentagon) or higher number of sides is fine. I wish Wikipedia would let draw on these answers, because I could draw hundreds of shapes with three right angles. When we talk of shapes, the most regular shapes come to mind, triangles, squares, pentagons, etc. But you did not spcify that my shape had to have straight sides. Imagine, for example, a circle which I will break at three places and insert right angles. Weird, but it does have three right angles. Do the right angles have to face in towards the center? I could even draw a more bizarre shape with with three right angles facing out, connected by curved lines.
An equilateral triangle
False - and false ! Not ALL angles are right-angles - and a triangle has THREE sides !
A triangle has three sides and three angles that total 180 degrees.
scalene triangle