angles and triangles
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Angles and Triangles. Presented By, Krishna kumari and Z,verghese KendriyaVidyalaya, I N S Hamla. - PowerPoint PPT PresentationTRANSCRIPT
Angles and Triangles
Presented By, Krishna kumari
and Z,verghese KendriyaVidyalaya,
I N S Hamla.
WE CAN DRAW A LINE SEGMENT ON A PAPER AND IT HAS DEFINITE LENGTHA RAY AND LINE HAVE NO DEFINITE LENGTH
TWO RAYS AND LINE SEGMENTS WITH THE COMMON END POINT
FORM AN ANGLE
A WHERE TWO END POINTS MEET IS
CALLED VERTEX
AND LINE SEGMENTS ARE CALLED ARMS
ACUTE ANGLE
A
B C
RIGHT ANGLE
A
B C
OBTUSE ANGLE
A
B C
Triangles-Introduction
• Definition: A plane figure bound by three lines in a plane is called a triangle.a triangle has 6 parts.(3sides & 3angles).
• Here,AB,AC&BC are the sides,A,B & C are points. A
B C
Triangle Definition: A triangle, HAS THREE LINE SEGM ENTS ,THR EE VERTIC E S
AN D THR EE ANGLES
A
B C
Types Of TrianglesOn the basis of sides: 1. Scalene triangles 2. Isosceles triangles 3. Equilateral triangles.On the basis of angles: 4.Acute triangles 5.Right triangles 6.Obtuse triangles.An equilateral triangle is an isosceles triangle but the converse
is not true.
Scalene Triangles• Definition: A triangle,no two of whose sides are equal, is called a scalene
triangle. E.g..
A
B
C
Isosceles Triangle Definition: A triangle, two of whose sides are equal, is called an isosceles
triangle.e.g.
A
B C
Equilateral Triangle• Definition: a triangle whose all sides are equal, is called an
equilateral triangle.e.g.
A
B C
Acute triangle• Definition:A triangle each of whose angles is acute is called an acute angled
triangle or simply acute triangle.e.g.
A
B C
Right Triangle• Definition: A triangle with one angle a right angle is called a right angled
triangle or simply right triangle.e.g.
A
B C
Obtuse triangle• Definition: A triangle with one angle an obtuse angle is known as obtuse
angled triangle or simply obtuse triangle.e.g.
A
B C
Triangle properties-1• Property 1:the sum of the three angles in a triangle is 180 degrees.
• Property 2:if a side of a triangle is produced then the exterior angle so formed is equal to the sum of the two interior opposite angles.
A
B C
Here, angle A+angle B+angle C=180 degrees.
A
B CD
Here,angle ACD = angle A+angle B