In this lesson you’ll be introduced to the definition, basics and uses of parallel
lines and Transversals in geometry. You’ll learn
it in the presentation by instructor in own handwriting, using video and with the
help of several examples with solution. It will be followed by explaining their
use to help you solve problems.
Two or more lines are called parallel lines if and only if the lines lie in the
same plane but do not intersect. The symbol used for parallel lines to each other
is
. E.g. Line
AB is parallel to CD is represented by AB
CD. When two lines are parallel, they have no points in common. A transversal
is
a line that intersects two or more lines (in the same plane), each at a different
point.
(More text below video...)
(Continued from above)
When lines intersect, angles are formed in several locations and names of
certain angles describe ‘where’ the angles are located in relation to the lines.
Transversal Postulate: This rule involves angles and transversals i.e. if a transversal
intersects two parallel lines, the corresponding angles are congruent. For example:
Given- AB
CD and
1 measures 60°.
Find other angles in the figure below:
You can solve this problem, using the following steps,
• since,
1 measures 60°,
2 shall be 120°
(this being supplementary to
1). By definition,
the supplementary angles are any two angles when they sum up to 180°.
•
1 and
3 are Vertical
Angles, as they two nonadjacent angles formed by two intersecting lines. Therefore,
3 = 60°. Then
4 = 120°(this being,
supplementary to
1).
•
1 and
5 are equal (by
transversal postulate)
• similarly,
6=2,
7=3
and
8=4
(by transversal postulate).
Winpossible's online math courses and tutorials have gained rapidly popularity since
their launch in 2008. Over 100,000 students have benefited from Winpossible's courses...
these courses in conjunction with free unlimited homework help serve as a very effective
math-tutor for our students.
-
All of the Winpossible math tutorials have been designed by top-notch instructors
and offer a comprehensive and rigorous math review of that topic.
-
We guarantee that any student who studies with Winpossible, will get a firm grasp
of the associated problem-solving techniques. Each course has our instructors providing
step-by-step solutions to a wide variety of problems, completely demystifying the
problem-solving process!
-
Winpossible courses have been used by students for help with homework and by homeschoolers.
-
Several teachers use Winpossible courses at schools as a supplement for in-class
instruction. They also use our course structure to develop course worksheets.
. E.g. Line
AB is parallel to CD is represented by AB
1 measures 60°.
Find other angles in the figure below:
