<PRE><B>Question 702281</B>
&lt;br&gt;&lt;font face=&quot;Tahoma&quot;&gt;An isosceles triangle has exactly two congruent sides.&lt;br&gt;

Let a stand for the length of those two congruent sides.&lt;br&gt;

Let b stand for the length of the base.&lt;br&gt;

Then we have:&lt;br&gt;

Eq 1: {{{72=2*a+b}}} given, because the perimeter {{{P=a+a+b}}}&lt;br&gt;

Eq 2: {{{b+4=a+a}}} given&lt;br&gt;

So, let&#39;s begin:&lt;br&gt;

{{{b+4=2a}}} simplifying Eq 2&lt;br&gt;

{{{b=2a-4}}}&lt;br&gt;

Now substitute this value for b into Eq 1:&lt;br&gt;

{{{72=2a+2a-4}}}&lt;br&gt;

{{{72=4a-4}}}&lt;br&gt;

{{{76=4a}}}&lt;br&gt;

{{{19=a}}}&lt;br&gt;

Now substitute this value for a into Eq 2:&lt;br&gt;

{{{b+4=19+19}}}&lt;br&gt;

{{{b+4=38}}}&lt;br&gt;

{{{b=34}}}&lt;br&gt;

So the length of the base of our triangle is 34 cm.&lt;br&gt;

Check it, it works!&lt;br&gt;

I hope this helps!  Keep practicing!  :)&lt;br&gt;

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