Name the different plane shapes needed to draw the net of
(i) A triangular prism
(ii) A cone
(iii) A square pyramid

Hint: Here we use the concept of plane shapes which are just two dimensional figures which can be made from straight lines or curves or both straight lines and a curve.
Some basic plane shapes are Triangle, Square, Circle etc.

Complete step-by-step answer:
(i) A triangular prism
We know a triangular prism looks like this

     
We can clearly see that both left and right face of the triangular prism are in triangle shape which are denoted by the triangles \[\vartriangle ABC,\vartriangle DEF\]
Also, the base and other two sides in the shape of the rectangle contribute in making of prism as that is the area between the two triangles.
So, the rectangles \[ACFD,ABED,BCEF\]are the three rectangles.
Therefore, plane shapes used to draw the net of a triangular prism are Triangle and Rectangle.

(ii) A cone
We know a cone looks like this

     
We can clearly see that the base of the cone is in circular shape which has diameter \[AB\].
Also, the curved surface on the top is formed by a sector \[ACB\]which is folded in such a way that the end points of the sides meet each other.
Therefore, plane shapes used to draw the net of a cone are Circle and a Sector.
(iii) A square prism
We know a square prism looks like this

     
We can clearly see that both upper and lower faces of the square prism are in square shape which are denoted by the squares \[ABCD,EFGH\]
Also, the four sides of the sphere prism are in the shape of a rectangle.

So, the rectangles \[ABGH,ADEH,DEFC,BCFG\]are the four rectangles.
Therefore, plane shapes used to draw the net of a squarer prism are Square and Rectangle.

Note: Students many times make mistakes while finding the plane shapes in cones and write triangles in place of sectors which is wrong because the conical part is curved and if we curve a triangle it will not form a cone.