yes a triangle is a solid figure
triangle. * * * * * A triangle is not a solid figure. However, a triangular pyramid (tetrahedron) is the correct answer.
A circle * * * * * On the right lines but a circle is not a solid figure. How about a sphere?
Anything 3 dimensional is solid.
A solid figure is a three-dimensional figure, such as a tetrahedron, cube, octahedron, dodecahedron, or icosahedron. A non-solid figure, such as a triangle, square, pentagon, etc... is a plane figure.
A square triangle
A triangle based pyramid (tetrahedron).
triangle based pyramids
The face of a triangle is the flat surface of the solid figure. _________________________________________________ A face is a side of a 3 dimensional figure. So, the number of faces a triangle would be 0.