An isosceles triangle has at least two equal sides (and therefore at least two equal angles).<br><br>
&bull; Equilateral triangle &mdash; all 3 sides equal, so it IS isosceles (it has at least two equal sides).<br>
&bull; Triangle with 2 equal sides &mdash; this IS isosceles by definition.<br>
&bull; Triangle with 2 equal angles &mdash; the sides opposite equal angles are equal, so this IS isosceles.<br>
&bull; Triangle with angles 30&deg;, 40&deg;, 110&deg; &mdash; no two angles are equal, so no two sides are equal. This is NOT isosceles.<br>
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Final Answer: D: Triangle with angles 30&deg;, 40&deg; and 110&deg;