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Which line is longer? C or D ? Measure each line. How good is your guess?

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प्रश्न

Which line is longer? C or D? Measure each line. How good is your guess?

योग
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उत्तर

I think both lines C and D are of the same measurement.

With the help of a ruler, we get the measurement of 3.2 cm for both lines.

So, our guess was correct.

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अध्याय 10: Tenths and Hundredths - Tenths and Hundredths [पृष्ठ १३७]

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एनसीईआरटी Mathematics Math - Magic [English] Class 5
अध्याय 10 Tenths and Hundredths
Tenths and Hundredths | Q 4.2 | पृष्ठ १३७

संबंधित प्रश्न

Ten millimetre makes one centimetre.


Match the following.

1. Length of the fore arm metre
2. SI unit of length second
3. Nano 103
4. SI Unit of time 10–9
5. Kilo Cubit

Metre is the unit of ______.


Have you seen frogs? Where? How many different types of frogs have you seen? Are all the frogs of the same length? Here are two interesting examples.


Guess the lengths to draw these things. Ask your friend to draw the same. After you make the drawing use a scale to measure the length. Whose drawing showed a better guess?

Guess its length
and draw
Measure of
your drawing
Measure of your
friend’s drawing
An ant of length
less than 1 cm
   
Pencil of length
about 7 cm
   
A glass 11 cm high with
water up to 5 cm
   
A bangle of perimeter
20 cm
   
A curly hair of length
16 cm
   

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


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


How many stamps can be placed along its length?


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 cm is the length of the boundary of lake A in the drawing?(use thread to find out)

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.

  • Find the area of lake B on the drawing in square cm. What is its actual area in square km?

What are the materials needed to find the length of a banana?


The distance between one end and the other end is called ______.


What is the unit of length?


  1. The earth-moon distance is about 60 earth radius. What will be the diameter of the earth (approximately in degrees) as seen from the moon?
  2. Moon is seen to be of (½)°diameter from the earth. What must be the relative size compared to the earth?
  3. From parallax measurement, the sun is found to be at a distance of about 400 times the earth-moon distance. Estimate the ratio of sun-earth diameters.

The distance of a galaxy is of the order of 1025 m. Calculate the order of magnitude of time taken by light to reach us from the galaxy.


In an experiment to estimate the size of a molecule of oleic acid 1 mL of oleic acid is dissolved in 19 mL of alcohol. Then 1 mL of this solution is diluted to 20 mL by adding alcohol. Now 1 drop of this diluted solution is placed on water in a shallow trough. The solution spreads over the surface of water forming one molecule thick layer. Now, lycopodium powder is sprinkled evenly over the film and its diameter is measured. Knowing the volume of the drop and area of the film we can calculate the thickness of the film which will give us the size of oleic acid molecule.

Read the passage carefully and answer the following questions:

  1. Why do we dissolve oleic acid in alcohol?
  2. What is the role of lycopodium powder?
  3. What would be the volume of oleic acid in each mL of solution prepared?
  4. How will you calculate the volume of n drops of this solution of oleic acid?
  5. What will be the volume of oleic acid in one drop of this solution?

Why is Earth's orbit used instead of its diameter to measure distances to stars using the parallax method?


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