Question 1179556
.


I solved this problem today 4 hour ago under this link


<A HREF=https://www.algebra.com/algebra/homework/Angles/Angles.faq.question.1179538.html>https://www.algebra.com/algebra/homework/Angles/Angles.faq.question.1179538.html</A>


https://www.algebra.com/algebra/homework/Angles/Angles.faq.question.1179538.html



For your convenience, I copy-paste my solution here AGAIN.



--------------



Let me start from the proper definition


<pre>

    +-------------------------------------------------------------------------+
    |   Alternate interior angles are angles formed when two parallel         |
    |   are intersected by a transversal.                                     | 
    |   The angles are positioned at the inner corners of the intersections   |
    |   and lie on opposite sides of the transversal.                         |
    +-------------------------------------------------------------------------+



One of the first theorem of Geometry states that alternate interior angles at two parallel lines are CONGRUENT, 
i.e. have equal angular measure.


It means that  A = B,   or


    2x = x + 30.


From this equation


    x = 30 degrees.


So, both angles A and B have equal measure of 2*30 = 60 degrees = 30+30 degrees.    <U>ANSWER</U>
</pre>

Solved.


----------------


About parallel lines and associated angles see the lesson

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/Angles/Parallel-lines.lesson>Parallel lines</A>

in this site.



///////////



Do not forget to post your &nbsp;"THANKS" &nbsp;to me for my teaching.