The given triangle is isosceles, so the two remaining angles in the triangle both have measure <em>xº</em>. The interior angles of any triangle sum to 180º, so that
58º + <em>xº</em> + <em>xº</em> = 180º
58 + 2<em>x</em> = 180
2<em>x</em> = 122
<em>x</em> = 61
Angles <em>y</em> and <em>z</em> are supplementary to angle <em>x</em>, so that
<em>xº</em> + <em>yº</em> = 180º
and
<em>xº</em> + <em>zº</em> = 180º
and consequently, <em>y</em> = <em>z</em>. In particular, we get
<em>y</em> = 180 - 61
<em>y</em> = 119
and so
<em>z</em> = 119
