<p>Point A is a vertex of an 8-sided polygon. The polygon has 8 sides of equal length and 8 angles of equal measure. When all possible diagnols are drawn from point A in the polgygon, how many triangles are formed</p>
<p>A- 4
B - 5
C - 6
D - 7
E - 8</p>
<p>Answer: C</p>
<p>/</p>
<p>and if anyone has the new blue book also this problem : pg 530 #17 </p>
<p>answer is 100 but i dont understand it completely. i understand why you divide the 80 / 4 and get 20 but why is it 5 inches that u multiply that by?</p>
<p>maybe its simple but i wanna know how to do this type of problem incase i see it tmw.</p>
<p>Point A is one of the 8 vertices of the 8-sided polygon. Therefore, a diagonal is able to be drawn to each of the other 7 vertices EXCEPT the 2 vertices directly adjacent to point A. 7-2 = 5 possible diagonals.</p>
<p>Each diagonal divides it into a separate triangle, and there is one leftover triangle after the diagonal division, forming six triangles, or choice C.</p>
<p>You can see in the diagram the for every 4 inches of the paper strip edge length, there 3 solid, linear inches of paper and an equilateral triangle with a side length of 1 inch. </p>
<p>So, for every 4 inches of the paper strip edge:</p>
<p>3 inches of solid paper + 1 inch side of triangle + 1 inch side of triangle = 5 inches</p>
<p>We know the entire paper strip is 80 inches long, so the number of 4 inch intervals =</p>
<p>80 / 4
= 20</p>
<p>But since we now know each of these 4 inch intervals is now a 5 inch interval, we multiply the # of intervals x 5.</p>
<p>20 x 5
= 100</p>
<p>So, the total length, in inches of the bold notched edge is 100 inches.</p>