contains 14 slides. It is about triangles.

1. TRIANGLES
Presented by:
Ann Treesa Sebastian

2. • Triangles – Basic concepts
• Regions – Interior, Exterior,Triangular
• Types of triangles
• Based on length of sides
• Based on the magnitude of the angles
• Equiangular triangles

3.  A triangle is a closed figure made of three line segments.
 It has three vertices, three sides and three angles.
 The line segments forming a triangle are the three sides of
the triangle.
 The point where any two of the three line segments of
a triangle intersect is called the vertex of the triangle.
 When two line segments intersect, they form an angle.
 A triangle is denoted by
A
B
C

4. o The region within the boundary of a
triangle is called the interior region of
the triangle.
o Points P, Q, S and R are in the interior of
∆ ABC.
o The region outside the boundary of a
triangle is called the exterior region of
the triangle.
o Points X, Y and Z are in the exterior of
∆ ABC.
o Points E, F and H are in the boundary of
∆ ABC.
o The interior region along with the
boundary is known as the triangular
region.

5. A triangle has three sides and three angles. Triangles can be
classified into different categories based on:
• the length of the sides
• the magnitude of the angles

6. Based on the length of the sides triangles are classified into the
following categories:
 Equilateral triangles
 Isoscles triangles
 Scalene triangles

7. When all the three sides of a triangle are equal it is
called an equilateral triangle.

8. If two sides of a triangle are equal in length, then it is
called an isosceles triangle.

9. A triangle having no two sides equal is called a scalene
triangle. That is all three sides have different length.

10. Based on the length of the sides triangles are classified into the following
categories:
 Acute - angled triangles
 Right - angled triangles
 Obtuse - angled triangles

11. If each of the three angles of a triangle are acute, that is
less than 90 degree, it is called an acute angled triangle or
simply an acute triangle.

12. When one angle of a triangle is a right angle, that is
90 degree, the triangle is called a right angled triangle
or simply a right triangle

13. When one angle of a triangle is a right angle, that is
greater than 90 degree, the triangle is called an obtuse
angled triangle or simply an obtuse triangle

14. When the three angles of a triangle are equal, the triangle is
known as equiangular triangle. An equiangular triangle is also
equilateral.