English

Can you think of how to cut a postcard so that you can pass through it? - Mathematics

Advertisements
Advertisements

Question

Can you think of how to cut a postcard so that you can pass through it?

Diagram
Advertisements

Solution

Yes, I can pass through a postcard by making a loop from it.

The steps are given below:


Make lines on the postcard as shown in this figure.

Cut the postcard along the lines which touch its border.

This will make a loop as shown here.

shaalaa.com
  Is there an error in this question or solution?
Chapter 11: Area and its Boundary - Area and its Boundary [Page 150]

APPEARS IN

NCERT Math - Magic [English] Class 5
Chapter 11 Area and its Boundary
Area and its Boundary | Q 7 | Page 150

RELATED QUESTIONS

The farthest objects in our Universe discovered by modern astronomers are so distant that light emitted by them takes billions of years to reach the Earth. These objects (known as quasars) have many puzzling features, which have not yet been satisfactorily explained. What is the distance in km of a quasar from which light takes 3.0 billion years to reach us?


The nearest star to our solar system is 4.29 light years away. How much is this distance in terms of parsecs? How much parallax would this star (named Alpha Centauri) show when viewed from two locations of the Earth six months apart in its orbit around the Sun?


Just as precise measurements are necessary in science, it is equally important to be able to make rough estimates of quantities using rudimentary ideas and common observations. Think of ways by which you can estimate the following (where an estimate is difficult to obtain, try to get an upper bound on the quantity):-

the number of air molecules in your classroom.


Write true or false.

Every measurement involves two things – a number and a unit.


What are the S.I. units of

  1.  mass
  2.  length
  3.  time and
  4.  temperature.

Write their names and symbols.


Exercise


500 gm = ______ kilogram.


Now guess the length and width of many other things. Measure and find the difference between your measure and your guess.

Size of Your guess in cm Your measure in cm
  Length Width Length Width
100 Rupee note        
10 Rupee note        
20 Rupee note        
5 Rupee note        
Post card        
Math-Magic book        

Difference in size
Do this for yourself and find the difference.


What is Dinesh’s height in metres? _____ m _____ cm.


So Anar also tried many different ways to make a boundary for 800 square meters of land.

He made rectangles A, B, and C of different sizes. Find out the length of the boundary of each. How much gold wire will he get for these rectangles?


  • Gold wire for A = _________ metres

  • Gold wire for B = _________ metres
  • C  
    Gold wire for C = __________ metres

But then Anar made an even longer rectangle... See how long!


  • So he will get __________ metres of gold wire!!

There are two beautiful lakes near a village. People come for boating and picnics in both the lakes. The village Panchayat is worried that with the noise of the boats the birds will stop coming. The Panchayat wants motorboats in only one lake. The other lake will be saved for the birds to make their nests.

  • What is the length of the boundary of lake B in the drawing?

There are two beautiful lakes near a village. People come for boating and picnics in both the lakes. The village Panchayat is worried that with the noise of the boats the birds will stop coming. The Panchayat wants motorboats in only one lake. The other lake will be saved for the birds to make their nests.

  • How many kilometers long is the actual boundary of lake B?

In which SI unit, you can measure your height?


What is the unit of measurements of very small lengths?


What is the unit of length?


Length is ______.


In the parallax formula D = b/θ, what must be true about the angle θ for the calculation to be correct?


What is an Astronomical Unit (AU)?


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×