**All About The New Door**

### Topic: **Standard Unit Of Length**

It is a beautiful morning. Triho has just woken up. He wants to go out and enjoy the sunny day in his backyard.

As he opens his back door, the entire door comes out. He is shocked. â€śHow did this happen? Oh no! I need to fix this quicklyâ€ť, he thinks. What will he do now? If there is no door, how will he be safe? Can you think of ways to help him?

Triho being Triho, he gets an idea. â€śI can get a new door. Let me measure the height and width of this door so that I can get a new oneâ€ť, he says to himself. He starts measuring the height using handspans. â€śThe height of the door is 8 handspans, and the width is 4â€ť, he says. Brilliant indeed.

â€śOh no! But I cannot leave the house open like this and get the new door. What do I do now?â€ť says Triho. His problems are not ending today. Suddenly, he remembers that there is a furniture store near Squarhoâ€™s house. He decides to call him.

While explaining everything to Squarho, he says, â€śThe door is 8 handspans long and 4 handspans wide. Do not forget thisâ€ť. Squarho leaves for the store nearby.

On reaching the store, he mentions the required size of the door. The shopkeeper gets the new door, and Squarho cross-checks it to see if the size is right. â€śIt is 8 handspans long and 4 handspans wideâ€ť, he says. He decides to buy it and leaves for Trihoâ€™s house.

But something strange happens. Triho is shocked and furious. â€śI told you the door was 8 handspans long and 4 handspans wide. You did not measure it right. What will I do with such a huge door?â€ť he says furiously.

Squarho is confused. Measuring the door again, he says, â€śSee, it is 8 handspans long and 4 handspans wideâ€ť. But Triho does not believe him. He blames him again for this. Squarho decides to call Uncle Math and seek his help.

â€śSquarho is not the wrong Triho. Because he has longer hands, his hand span is longer. Whereas your handspan is smaller than him. Thus the difference in the sizeâ€ť, explains Uncle Math.

â€śOh right! We did not even realize this. This proves that handspans and any other non-standard units of measurement are not a perfect way to measure. Then how do we measure things?â€ť says Triho. Undoubtedly Uncle Math must have a solid solution for this. Let us find out.

â€śNo fear when I am hereâ€ť, says Uncle Math. â€śTo solve this problem, standard units of measurements were introduced. These units are used by everyone to have uniformity and avoid similar confusion. The most common standard units of measurements are **centimetres** and **metres**â€ť, he explains.

â€śMeet my new gadget Mr Length. He will help us measure the door correctlyâ€ť, says Uncle Math. Mr Length is a remote-like gadget with a special tape attached to it. The tape has small and big lines and some numbers written on it. It also has a screen to display the numbers.

Uncle Math first opens the measuring tape. He then keeps 0 of the scale on one end of the door. Then drags the ruler to the other end of the door. â€ś200 centimetres (cm) heightâ€ť, he reads. Then he repeats the process to measure the width of the door. â€ś100 centimetres (cm)â€ť, he says.

â€śWow! This was so simpleâ€ť, says Triho. They try their hands on Mr Length and measure the door again.

â€śAlright! Now, let us go to the store again to get the door exchangedâ€ť, suggests Squarho. They leave for the store.

â€śOh no! We need the measurement in meters to give you the right doorâ€ť, asks the shopkeeper. Triho and Squarho are disappointed. â€śBut how can we give a centimetre as a metre?â€ť questions Triho. â€śWe can. We will have to convert centimetres into metres for that. Mr Length will help us againâ€ť, says Uncle Math.

â€śMr Length convert 100 cm into metre, go!â€ť says Uncle Math. â€ś1 metreâ€ť, it announces. â€śPerfect. That means 200 cm makes 2 metres(m). So my door is 2 m long. And since it is 100 cm wide, it means it is 1 m wideâ€ť, says Triho. â€śWell done!â€ť appreciates Uncle Math.

The shopkeeper gives them a door that is 2 m long and 1 m wide. Squarho and Triho are delighted. Now, they can easily fix this new door. Together they leave the shop with the door.

The new door looks perfect. â€śIn frustration, I screamed at you. But I do not like it when I am unable to solve any problem. Please do not mind from next timeâ€ť, clarifies Triho. Squarho likes how Triho solved misunderstandings between them. A new door, zero misunderstandings, and a day full of measurements, counts as a good day indeed.

**We Learnt That…**

- Non-standard units of measurements lead to confusion and are not the best way to measure length.
- Standard units of measurements are used worldwide and promote uniformity.
- Centimetres (cm) and metres (m) are standard units of measurement.
- 100 cm makes 1 metre.
- Open communications reduce misunderstandings and strengthens relationships.

**Letâ€™s Discuss!**

- Why was I upset?
- What was the confusion? Why did it happen?
- Who is Mr Length? What is special about it?
- What are the standard units of measuring length?
- What is the relationship between metre and centimetre?