Triangle
It could be a square or a rectangle. Or you could call it a quadragon.
An octagon.
A decagon.
A hendecagon.
A dodecagon.
It area.
Every triangle has at least three angles.
it is a trigon or as most people call it triangle
No, the sun is not a plane figure. It is a 3-dimentional astronomical object we call a star. Plane figures have just two dimensions.
You call it a geometric shape that is unknown to call a triangle which also affects the square because the square is not an illegal polygon, which will then lead to a Circle or a sphere as you may say it. Next it would've turned in to a rhombus with a square base. www.geometricsystems.com/shapes
A polygon.
You call a plane with two set of wings a Biplane.A plane with one set of wings is called a monoplane.A plane with three set of wings is called a triplane.