Question

How many windows are there in the big room?

A. $1$
B. $2$
C. $3$
D. $4$

Answer 1

Hint: First, we will understand how to visualise different shapes and then we will understand what different types of views are in a three dimensional shape and then we will analyze our question figure and count the number of windows in both kinds of view. After that we will add them together and get the total answer.

Complete step by step answer:
To solve questions like this we need visualisation and we must understand how to visualise solid shapes.
Now we know that plane figures or shapes have two measurements namely length and breadth. Hence, they are called two-dimensional shapes whereas a solid object which has three measurements that is the length, breadth, height or we can also say depth. Hence, they are called three-dimensional shapes.
Two-dimensional and three-dimensional figures can also be briefly named as 2-D and 3-D figures, respectively. Let’s take some example of two-dimensional figures:

Now, let’s take some example of three-dimensional figures:

Three-dimensional figures have different numbers of faces, edges and vertices. All the flat surfaces of the figure are called faces, these faces are 2-D shapes. The line segment where the faces of three-dimensional figures meet each other is called the edge of the shape. The corners or points where the edges of the figure meet each other are called vertices.
A three-dimensional object or shape can look differently from different positions (or sides) so they can be drawn from different perspectives, this is called visualising a solid shape. For example:

We will now form a side view, front view and top view:
 

Now, for the given figure in question that is :

We see that on the left side it is front view whereas on the right hand side it is side view. We see that there is only one window on the front view and two windows on the side view. Therefore, the number of windows in the room will be $1+2=3$ .

So, the correct answer is “Option C”.

Note:
We must always give examples when we describe visualisation of different kinds of views. In the above three kinds of views one side of a solid has two rectangular surfaces which are vertically connected, front view has three rectangle surfaces in L shape and top view has two rectangle surfaces which are horizontally connected.