A triangle has three sides in total. If it has more than three sides, it is not a triangle. One of the three sides is called the 'base' ... usually the side that the triangle is resting on.
An octagon is a plane figure. It has eight sides, but no real base.
2 sides, the base and the cone.
5 sides
One side will be a square. It is the base. The lateral sides are triangles.
5... base and one triangle on each side
4 triangular sides and 1 square base
The base of a trapezium is one of the parallel sides. Conventionally it is the longer of the two parallel sides but that need not be the case.
With a triangle base there are four sides including the base
4 the base and 3 sides
a triangular pyramid has 4 triangular sides
Five.