Download maths two 4 - THE KV POWER POINT

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
LENGTH
A 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
TrianglesIntroduction
• 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
A & C are points.
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 Triangles
On 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..
C
A
B
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.
A
Here, angle A+angle
B+angle C=180 degrees.
C
B
• 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.
Here,angle ACD = angle
A+angle B
A
B
C
D