Introductory Video - Triangles, Math, Class 9 Video Lecture - Class 9 | Best Video for Class 9

I'm sure each one of you knows what a
triangle is but have you ever seen
structures in real life which is made of
triangles or which uses triangles to
form a part or other let me show you
some such figures this is a curved dome
which has many triangles joined
side-by-side this is a pyramid of Egypt
which has four triangular faces now try
to find out some other examples in your
surroundings Hey are these triangles
used only for decorative purpose the
answer is no and the reason was given by
an engineer an architect Richard
buckminster fula he explained that a
triangle when combined with other
identical units provides solidity
support and light weight to a structure
these identical geometrical units are
congruent triangles have a look at this
bridge it involves many triangles in its
construction the Disney Epcot Center
dome is made entirely of triangles which
keep it very strong isn't it interesting
now let us go through the chapter to get
more knowledge about congruent triangles
in this chapter you will learn to solve
problems based on SAS congruence
criterion a SI congruence criterion a a
S congruence criterion sss congruence
criterion RHS congruence criterion you
will also study properties of isosceles
triangles and triangle inequality after
studying this chapter you will
understand more about triangles and
their use in real-life constructions and
various methods of applying congruence