<p>There are 10 points in the plane and no three of which are collinear. How many unique (defined by points, not area or perimeter) triangles can be formed?</p>
<p>Would you think me crazy if I said 120?</p>
<p>umm im getting 120?
whats the answer?</p>
<p>The answer is 120, you two are correct. I'll now post my "solution" for those who couldn't get it: </p>
<p>Since no three points are collinear, we may assume that each grouping of 3 points constitutes a distinct triangle. So we used the combination formula to get the expression 10!/[(7!)(3!)] which yields 120.</p>