Parallel Lines : In geometry, parallel lines are lines in a plane which do not meet; that is, two lines in a plane that do not intersect or touch each other at any point are said to be parallel. Perpendicular Lines : Perpendicular means "at right angles". A line meeting another at a right angle, or 90° is said to be perpendicular to it.

1. Green University Of
Bangladesh
Name : Md. Toufiq Elahi
ID : 153002030
Department : Computer Science and
Engineering(CSE)

2. Topics
Parallel
&
Perpendicular

3. Parallel Lines :
 In geometry, parallel
lines are lines in a plane which do
not meet; that is, two lines in a
plane that do not intersect or
touch each other at any point are
said to be parallel.
Example :
Parallel lines in real
life

4. Perpendicular Lines :
 Perpendicular means "at
right angles". A line meeting
another at a right angle, or 90°
is said to be perpendicular to
it.
Example :
Perpendicular lines in
real life

5. Find the equation of line passing through(-5, 6)
and a) Parallel, b) Perpendicular, to 7x-8y=9 ?
 a ) Solution Parallel Line :
Given that,
7x-8y=9
=>7x-8y-9=0 -----------(1)
(1)Let the equation of the state line
parallel to (1) be,
7x-8y-k=0 ----------------(2)
Since (2) passes through (-5, 6) so
we get,
7(-5)-8(6)-k=0
=>-35 -48-k=0
:. K=-83
The required equation is,
7x-8y-(-83)=0
=>7x-8y+83=0
(Answer.)

6. b) Solution perpendicular Line :
Let the equation of straight line perpendicular to (1) be,
8x-7y-k=0 ------------------(3)
Since (3) passes through (-5, 6) so we get,
8(-5)+7(6)-k=0
=>-40+42-k=0
:. K=2
S0 the required equition is,
8x+7y-2=0
(Answer.)

7. Thank You