Fun with lines

Fun with lines

What shapes can you draw with 3 lines or 4 lines or 5 lines?

We have already seen some shapes with names like triangles, rectangles and squares.

Here is a shape which is in the form of a fish (see Fig. 4.1).

It has 5 lines. Can you draw a fish with 4 lines or with 3 lines? Think!

1. Only two lines

What shapes can you draw with only TWO lines?

The following forms are possible with 2 lines. Isn’t it?

Is there something you notice in all these shapes?

2. Only one line

What shapes can be drawn with only ONE line? The line may be standing upright, lying flat, or slanting. Perhaps it can be, slant left or slant right. It may be long or short.

Now, consider the following situation.

The teacher gives Yazhini a paper with a line drawn on it and asks Akilan to draw the same line on the black board, as instructed by Yazhini. Then they shall reverse the process. They do the same with other shapes using 2 lines and 3 lines. Try doing this and say, whether this is easy to do!

Observe the following conversation.

Teacher: Sakthi, can you say how to draw lines?

Sakthi: Yes Teacher! Why only lines? I may like to draw curves and circles too!

Teacher: Sakthi, you can do all the shapes you like. But you see, there is enough difficulty in describing shapes made only of lines. So, we will get to curves and circles later.

Sakthi: Teacher, Why should we describe shapes? We can just draw and show them when we want.

Is Sakthi right?

In Mathematics, every thinking is interesting and unlimited. Remember numbers; it is not stopped with adding 2 – digits. Numbers go on endlessly and it is possible to add any two numbers, however large. We know that even a 37- digit number ending in 0 is divisible by 5.

It is the same with shapes too. We are interested in lines, triangles, rectangles and in whatever the shapes may be and the size however large or small. We need to give them names not only to describe them but also to explore a lot with them.