Answer: Option A. ->
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We need a square with same side length as that of the triangle. The resultant solid is known as a square pyramid.

Answer: Option A. ->
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Each part: 1 Mark
(a) By visual estimation, it is easy for us to see that 3 more cans can fit in the empty space. Hence, we can say that there will be 12 cans on a full shelf.
(b) The front side of the figure is a pentagon.

Answer: Option A. ->
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Answer: 1 Mark each
The key feature of a sphere is that every point on the surface of a sphere is equidistant from the centre.
The normal definition of faces, vertices and edges are not appropriate for a sphere because it is not a polyhedron.

Answer: Option A. ->
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Explanation: 2 Marks
A square prism has a square as its base. However, its height is not necessarily same as the side of the square.
Thus, a square prism can also be a cuboid.
All cubes are square prism but all square prisms need not be cubes.

Answer: Option A. ->
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(a) Diagram of each view: 0.5 Mark 
(b) Diagram of each view: 0.5 Mark
(a)


(b)
  

Answer: Option A. ->
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Definition: 2 Marks
Example: 1 Mark
A shape that has only two dimensions (such as width and height) and no thickness is known as 2-D shape. In 2-D shapes, the sides are made of straight and curved lines. 
Example: squares, circles, triangles
A 3-D shape is a solid which encloses volume and has length, breadth and height. 3-D shapes have four properties that set them apart from 2-D shapes: faces, vertices, edges and volume. 
Example: sphere, cylinder, cube

Answer: Option A. ->
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Explanation: 1 Mark each
A cylinder can be thought of as a circular prism that is a prism with a circle as its base.
A cone can be thought of a circular pyramid that is a pyramid with a circle as its base.

Answer: Option A. ->
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Each correct match: 1 Mark

Answer: Option A. ->
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Each part: 1 Mark
From visual estimation, each column contains 4 boxes.

(a)  6 columns can be fit in the shelf.
In the 5th column, there is space for 2 more boxes.
and in the 6th column, there is space for 4 boxes.
$\therefore$ Number of boxes on the full shelf = 18 + 2 + 4 = 24 boxes
(b) If the length of the shelf is doubled, the shelf can have 12 columns.
If the height of the shelf is doubled, then each column can have 8 boxes.
$\therefore$ Total number of boxes on the full new shelf:
= $12\times 8$
= 96 boxes
(c) If the length of the shelf is halved, the shelf can have 3 columns.
If the height of the shelf is doubled, then each column can have 8 boxes
$\therefore$ Total number of boxes on the full new shelf:
= $3\times 8$
= 24 boxes
(d)  If the length of the shelf is doubled, the shelf can have 12 columns.
If the height of the shelf is doubled, then each column can have 4 boxes.
$\therefore$ Total number of boxes on the full new shelf:
= $12\times 4$
= 48 boxes

Answer: Option A. ->
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Each Part: 1.5 Marks
(a) When we put the cubes side by side, the lengths of both the cubes are added, but there will be no change in the breadth and height of the cube.
Length (l) = (3 + 3) = 6 cm.
Breadth (b) = 3 cm.
Height (h) = 3 cm.
Hence, $l+b+h=6+3+3=12cm$
(b) Since the metallic cylinder is melted to form a cube, the cube will be of the same volume as that of the cylinder.
Volume of cube  =  Volume of cylinder
$a^3=1331c{m}^3$
$a=\sqrt[3]{3(}1331)=11cm$