Other polygons
There are many other polygons, some of which are given in the table below.
Table of some polygons and their number of sides.
Sides
Name
5
pentagon
6
hexagon
7
heptagon
8
octagon
10
decagon
15
pentadecagon
Examples of other polygons.
Angles of regular polygons
You can calculate the size of the interior angle of a regular polygon by using:
$$\widehat{A}=\frac{n-2}{n}\times {180}^{\circ}$$
where
$n$ is the number of sides and
$\widehat{A}$ is any angle.
Areas of polygons
Area of triangle:
$\frac{1}{2}\times $ base
$\times $ perpendicular height
Area of trapezium:
$\frac{1}{2}\times $ (sum of
$\parallel $ (parallel) sides)
$\times $ perpendicular height
Area of parallelogram and rhombus: base
$\times $ perpendicular height
Area of rectangle: length
$\times $ breadth
Area of square: length of side
$\times $ length of side
Area of circle:
$\pi $ x radius
${}^{2}$
Khan academy video on area and perimeter
Khan academy video on area of a circle
Polygons
For each case below, say whether the statement is true or false. For false statements, give a counter-example to prove it:
All squares are rectangles
All rectangles are squares
All pentagons are similar
All equilateral triangles are similar
All pentagons are congruent
All equilateral triangles are congruent
Find the areas of each of the given figures - remember area is measured in square units (cm
${}^{2}$ , m
${}^{2}$ , mm
${}^{2}$ ).
Summary
Make sure you know what: quadrilaterals, vertices, sides, angles, parallel lines, perpendicular lines,diagonals, bisectors and transversals mean.
Similarities and differences between quadrilaterals
Properties of triangles and quadrilaterals
Congruency of triangles
Classification of angles into acute, right, obtuse, straight, reflex or revolution
Theorem of Pythagoras which is used to calculate the lengths of sides of a right-angled triangle
Angles:
Acute angle: An angle 0 and 90
Right angle: An angle measuring 90
Obtuse angle: An angle 90 and 180
Straight angle: An angle measuring 180◦
Reflex angle: An angle 180 and 360
Revolution: An angle measuring 360
Angle properties and names
Equilateral, isoceles, right-angled, scalene triangles
Triangles angles = 180
Congruent and similar triangles
Pythagoras
Trapezium, parm, rectangle, square, rhombus, kite and properties
Areas of particular figures
Exercises
Find all the pairs of parallel lines in the following figures, giving reasons in each case.
Find angles
$a$ ,
$b$ ,
$c$ and
$d$ in each case, giving reasons.
Which of the following claims are true? Give a counter-example for those that are incorrect.
All equilateral triangles are similar.
All regular quadrilaterals are similar.
In any
$\u25b5ABC$
with
$\angle ABC={90}^{\circ}$ we have
$A{B}^{3}+B{C}^{3}=C{A}^{3}$ .
All right-angled isosceles triangles with perimeter 10 cm are congruent.
All rectangles with the same area are similar.
Say which of the following pairs of triangles are congruent with reasons.
For each pair of figures state whether they are similar or not. Give reasons.
Challenge problem
Using the figure below, show that the sum of the three angles in a triangle is 180
${}^{\circ}$ . Line
$DE$
is parallel to
$BC$ .
Questions & Answers
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
I only see partial conversation and what's the question here!
what about nanotechnology for water purification
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
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?
What is meant by 'nano scale'?
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
what is Nano technology ?
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?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
how did you get the value of 2000N.What calculations are needed to arrive at it
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Source:
OpenStax, Siyavula textbooks: grade 10 maths [ncs]. OpenStax CNX. Aug 05, 2011 Download for free at http://cnx.org/content/col11239/1.2
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