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K J Somiaya Comprehensive College of education. PPT presentation of CAP
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K J Somaiya Comprehensive College of Education, Training & Research
Name : Monica PandaRoll No : 44Subject : MathematicsTopic : QuadrilateralsStandard : VII
Road Map
• Objective• Definition• Introduction• Properties• Evaluation
OBJECTIVE:
At the end of the lesson, the students should be able to know the properties of quadrilaterals
Definition• Polygon – a closed many straight-
sided figure.
triangle parallelogram
octagonheptagonhexagon
pentagon
Definition• Quadrilateral – a polygon with 4
angles and 4 straight sides.
Quadrilateral Family
parallelogram
rectangle
rhombus square
trapezoid
INTRODUCTION
• WORD QUADRILATERAL IS DERIVED FROM
TWO WORDS “QUADRI” MEANS “FOUR” AND
“LATERAL” MEANS “SIDES”.
8
Quadrilaterals
• A quadrilateral is a four-sided figure like the one shown. The sides are line segments connected together at their endpoints, called the vertices (plural of vertex) of the quadrilateral.
• A quadrilateral is named by its vertices.
• We call this quadrilateral ABCD or BADC or CDAB etc. (We start with a vertex and then proceed around the quadrilateral, either clockwise or counterclockwise.)
A
B
CD
* In quadrilateral ABCD, the vertices are A, B,C, and D* Adjacent vertices are :
A and BB and CC and DD and A
* Opposite vertices are :A and CB and D
A
B
CD
* Adjacent sides -Two sides with common vertex are :AB and BCBC and CDCD and DADA and AB
* Opposite sides are:AB and DCAD and BC
A
B
C
D
• Adjacent angles - Two angles with a common sides are: <A and <D<D and <C<C and <B<B and <A
• Opposite angles are :<A and <C<B and <D
AB
CD
• 4 vertices
A.
B.
C.
D.
• 4 sides• 4 angles
QUADRILATERALSQUADRILATERALS
Segments joining opposite vertices like AC and BD are called diagonals of the quadrilateral. There are 2
diagonals in a quadrilateral.
A
D C
B
QUADRILATERALSQUADRILATERAL
EXTERIOR OF
QUADRILATERAL
INTERIOR OF
QUADRILATERAL
A
B
CD
E.
.
..
.
. GH
F
J
I
PROPERTIES OF A QUADRILATERAL
• IF A LINE CONTAINING ANY ONE OF THE FOUR SEGMENTS PQ, QR, RS, QS IS DRAWN, THEN REMAINING TWO POINTS LIE ON THE SAME SIDE OF THIS LINE.
P
R
Q
S
• The sum of all the angles equals 360º degrees.
70º
110º
70º
110º
70º70º
110º110º+
360º
QUADRILATERALSEXPERIMENTEXPERIMENT
AIM:AIM: To verify that the sum of 4 angles of a quadrilateral is 360 degree.
1. Draw 2 [congruent] quadrilaterals of same shape and size.
QUADRILATERALS
2. Draw arcs of same radii at the 4 vertices of the quadrilateral.
3. Colour the region enclosed as shown in the figure.
QUADRILATERALS4. Glue the figure1 in the note book.
5. Separate the angles in figure2 by zig-zag lines as shown.
QUADRILATERALS6. Cut the 4 angles of figure2 as shown.
QUADRILATERALS
7. Arrange the angles and paste them side by side.OBSERVATIONS:
4-angles of quadrilateral can be assembled in to a circle.
4-angles of a quadrilateral gives a complete angle.
The sum total of the 4 angles of quadrilateral is 3600.
EVALUATION
• Examples of shapes or curves that are not classified as quadrilaterals. They do not follow the definition of a quadrilateral. Can you give a reason why?
Are They Quadrilaterals?
ACB
Observe the figure and answer the following questions:
1. Name the points in the interior of the quadrilateral PQRS ?
2. Name the points in the exterior of the quadrilateral PQRS ?
3. Name the points on the quadrilateral PQRS ?
VW
Y
XU
T.
. . ..
.
RS
QP
What is the missing angle?
81º58º
109º?
A
D C
B
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