A polygon<span> has as many interior </span>angles<span> as sides. An equilateral triangle has three equal 60 </span>degree angles<span>. The </span>sum<span> of the </span>angles<span> of this and any triangle is </span>180 degrees<span>.The </span>sum<span> of the four interior </span>angles<span> of a square is 360 </span>degrees<span>, which is the same for any quadrilateral.</span>
So the probability is the number of favorable outcomes divided by the number of total outcomes. This means that the favorable outcomes are 7/9, and the unfavorable outcomes are 2/9. The odds against the event are the unfavorable outcomes. Therefore the odds against the event is 2/9, or 0.2 repeating. Hope this helps. Feel free to ask more questions, and feel free to ask questions about my explanation.