# 4.10 Compare sizes

 Page 1 / 1

## Memorandum

 3 cm 2 cm 10 cm 6 cm 6 cm 4 cm 20 cm 24 cm 9 cm 6 cm 30 cm 54 cm 15 cm 10 cm 50 cm 150 cm
3. (a)

(b) 2 twice more; 3 times more;

5 times more than first rectangle

(c) 16 times

4.2.1 – 4.2.4 Check learner’s effort.

## Activity: compare sizes [lo 4.2, lo 3.8]

3. LET US COMPARE SIZES!

The following rectangle has been enlarged first two times, then three times and then five times.

All the rectangles have the same ratio for length to breadth: 3:2.

a) Look again at the rectangles above. Suppose that each block is 1 cm by 1 cm. Complete the table.

 Rectangle Length Breadth Perimeter Area 1 __________ __________ __________ __________ 2 __________ __________ __________ __________ 3 __________ __________ __________ __________ 4 __________ __________ __________ __________

b) What happens to the perimeter each time the rectangle is enlarged?

_____________________________________________________________________

_____________________________________________________________________

c) How many times larger is the area if the rectangle is enlarged four times?

_____________________________________________________________________

4.1 Did you know?

The ratio to scale is always written in a specific way:

The first number refers to the drawing/plan.

The second number refers to reality.

A scale of 1:5 means that the length is 5 times smaller than in reality.

A scale of 5:1 means that the length is 5 times bigger than in reality.

4.2.1 Use the graph paper and enlarge the sketch on a scale of 4:1.

4.2.2 Enlarge this drawing on a scale of 1:2.

4.2.3 Reduce this sketch on a scale of 2:1.

4.2.4 BRAINTEASER!

• Can you enlarge this drawing and re-draw it?

## Assessment

Learning Outcome 3: The learner will be able to describe and represent characteristics and relationships between two-dimensional shapes and three-dimensional objects in a variety of orientations and positions.

Assessment Standard 3.8: We know this when the learner locates positions on co-ordinate systems (ordered grids) and maps

Learning Outcome 4: The learner will be able to use appropriate measuring units, instruments and formulae in a variety of contexts.

Assessment Standard 4.2: We know this when the learner solves problems.

#### Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Good
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

### Read also:

#### Get the best Algebra and trigonometry course in your pocket!

Source:  OpenStax, Mathematics grade 7. OpenStax CNX. Sep 16, 2009 Download for free at http://cnx.org/content/col11075/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Mathematics grade 7' conversation and receive update notifications?

 By Jonathan Long By Brooke Delaney By By Frank Levy By Jams Kalo By OpenStax By Jonathan Long By OpenStax By Jonathan Long By OpenStax