<p>What is the perimeter of the figure above?
a. 24
b. 25
c. 28
d. 30
e. 36</p>
<p>You're gonna need the book to look at the diagram. I got it right but I had just guessed. I want to know how to really do it.</p>
<p>This is a pretty tricky one. First, connect the two points at the base to form a triangle using the two slanted lines. Now notice that both the base angles of this triangle must be 60 degrees, since their complements are 30 degrees. That means the triangle is equilateral. You know the base of the triangle (the line you drew) is 6 because the opposite side is 6, so that means the two slanted lines are 6 as well. Now you can find the perimeter by adding up all the sides, 6+6+6+6+6=30.</p>
<p>Awesome kthnx a lot man!</p>
<p>No problem. I tried doing a bunch of trig stuff before I realized that was all you have to do :P</p>
<p>I had trouble with that one too. I'm not sure why my approach didn't work, but it didn't.</p>
<p>If you complete the two triangles by drawing lines to the base, you have two 30-60-90 triangles, right? Since one side is 6, we know the base is 3 and the hypotenuse is 3 * sqrt(3). Is that correct? Now, since we know that the bases of both triangles are three, and the base of the whole thing is 6, there is no overlap.</p>
<p>So why isn't the answer 2 * 3sqrt(3) + 6 + 6 + 6?</p>
<p>(Plus you lost me at the 'You know the base of the triangle (the line you drew) is 6' part :p)</p>
<p>The base is 6 because the top part already drawm is 6. It makes a square with a triangle in it. All sides of a square are equal so the base will be 6. then since the other 2 angles are 30 each and a square has 4 90 angles the angles at the bottom are 90-30=60 each. Since each angle is 60 in it it is equillateral and the two legs that make the triangle are 6 as well.</p>
<p>
[quote]
If you complete the two triangles by drawing lines to the base, you have two 30-60-90 triangles, right? Since one side is 6, we know the base is 3 and the hypotenuse is 3 * sqrt(3). Is that correct? Now, since we know that the bases of both triangles are three, and the base of the whole thing is 6, there is no overlap.</p>
<p>So why isn't the answer 2 * 3sqrt(3) + 6 + 6 + 6?
[/quote]
</p>
<p>lol, that's the same thing I tried at first. The vertical edge of the two triangles on the sides actually isn't 6, even though 6's are printed there. Why? Look at the hypotenuses (hypoteni?) of the triangles, they don't reach all the way to the top of the figure, so if you're going to make a right triangle you have to chop off a little bit of those two vertical lines, making them shorter than 6. In fact, using trig you can figure out that they're 3sqrt3 or about 5.2</p>