The inside of a two dimensional shape is called the area.
A triangle is a 3 sided shape. There are a few types, Isosceles, Scalene (Acute and Obtuse), Equilateral and the Right angle triangle.
A semi-circle is a two dimensional figure so it can have area but NOT volume. To find the area of a semi-circle see the question below.
Earth is three-dimensional, but maps are two-dimensional.
A planar projection is one wherein the points from a three-dimensional object are mapped on a two dimensional surface. One example is seen when a map of the world is projected on a flat page.
A sphere is a three-dimensional shape with one surface. Or: An irregular blob, an ellipsoid, a torus, plus other shapes. The most interesting 3D object with only one side is of course the Moebus strip.
the difference between a two dimensional shape and and a solid is that a two dimensional shape is plane and a solid you can see the whole shape a the inside.
A two dimensional figure would be an oval or ellipse. A three dimensional shape could be called an ovoid.
12-sided two dimensional shape: dodecagon12-sided three dimensional shape: dodecahedron
A two-dimensional shape that can be folded into a three-dimensional figure is often called a net.
When two sides (called faces) of a 3-dimensional shape meet, they meet at an edge.
That is called a polygon.
A shape that has 10 sides (two dimensional) is called a decagon. A shape that has 10 faces (three dimensional) is call a decahedron.
A hexahedron is a three-dimensional geometric shape having six sides; a hexagon is a two-dimensional six-sided shape.
If a polygon (2 dimensional shape) then it is a 2000-gon. If a polyhedron (3 dimensional solid), then it is a 2000-hedron.
A hexagon, if flat (two-dimensional).
A polygon is a two-dimensional shape. A cube has three dimensions, and is thus not a polygon.A three-dimensional solid shape (such as a cube) is called a polyhedron.
A polygon; specifically a tetragon. A two-dimensional shape with four equal sides and four right angles is a square. A two-dimensional shape with two sets of equal sides and four right angles is a rectangle. A two-dimensional shape with two sets of equal sides and two sets of equal angles is a parallelogram. A parallelogram where each opposite angel bisects the shape is a rhombus. A two-dimensional shape with one set of equal, parallel sides and two sets of equal angles is a trapezoid. A three-dimensional shape with four triangular faces is a tetrahedron.