Question

Fill in the blanks:
A brick has __________ faces and _______ edges.

Answer 1

Hint: A brick is a 3-dimensional solid cuboid. Hence it has 6 rectangles joined together. The face of an object is a flat surface which makes up the object, while an edge is the line on the boundary that joins two vertices together. Now, for a cuboid we have 6 faces which are meeting on 12 lines, so there are 12 edges.

Complete step-by-step answer:
Now, to establish the number of faces and edges of a brick, let us first understand the structure of a brick. A brick is basically a cuboid, that is a three dimensional rectangle which looks like:

Now as we can see, from the figure, the cuboid can be understood to be made up of 6 rectangles. Two rectangles with dimensions $l \times b$ each form the upper face and lower face of the cuboidal brick.
Next, we have two rectangles of dimensions $h \times b$ which make up the two side faces of the cuboidal brick.
Next, we have two rectangles of dimensions $h \times l$ which make up the front and back face of the cuboidal brick.
Hence, in all we have 6 faces of a cuboid which are made up 3 pairs of rectangles making the up, bottom, front, back, left and the right side of the cuboid. An edge is the line where the faces meet, joining the two vertices of a side. So, there are 2 pairs of horizontal edges and 2 pairs of vertical edges and 2 pairs of edges on the sides.
That is, 4 horizontal edges, 4 vertical edges and 4 edges on the sides.
Therefore, there are a total of 12 edges.
Hence, a brick which is a cuboid has a total of 6 faces and 12 edges.

Note: A cube and a cuboid are very similar having 6 faces. A cube is made up of 6 squares, hence all dimensions of a cube are equal, such that the volume of a cube of side a' units becomes ${a^3}$ while its total surface area is $6{a^2}$ square units.