Question 1138612
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<pre>
If the base and a leg of one isosceles triangle are congruent to the base and a leg of another isosceles triangle,

then these triangles have three pairs congruent sides.


    Do you understand it ?


It means, due to SSS triangles congruence test, that the triangles are congruent.


Hence, their corresponding angles are congruent.


The vertex angles are corresponding - so, they are congruent.
</pre>

The proof is completed.


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&nbsp;&nbsp;&nbsp;&nbsp;<A HREF=https://www.algebra.com/algebra/homework/Triangles/GEOMETRY-your-online-textbook.lesson>GEOMETRY - YOUR ONLINE TEXTBOOK</A> 

in this site.


The part of this online textbook, most relevant to your problem is the topic &nbsp;"<U>Properties of triangles</U>".


You may learn A LOT from there.


Save the link to this online textbook together with its description


Free of charge online textbook in GEOMETRY
https://www.algebra.com/algebra/homework/Triangles/GEOMETRY-your-online-textbook.lesson


to your archive and use it when it is needed.