<p>Could someone help with two problems:</p>
<p>Page 683 #13
and
Page 586 #18</p>
<p>Sorry but I can't write them down here because they have diagrams. </p>
<p>btw they're not on the consolidated list</p>
<p>for #18
triangle DEF is equilateral meaning each has 60 degree angles
line BDA is composed of angles BDE(50) EDF(60) and ADF( which u can find is 70, since 180-60-50=70)
ABC is isoceles, so since the top is 30, the other two are 75 each (DAF)
so, DAF = 75, and ADF = 70, 180 - 70- 75 = 35 degrees (B)</p>
<p>for #13
Z = 30,
so, the other interior angles have to equal 150
so Y + X must equal watever is left out of the 360 degrees thats there
360 - 150 = 210</p>
<p>that ones harder to explain, maybe someone can do it better</p>
<p>I'll try my best-</p>
<p>13)
-The measure of the angle adjecent to y is 180 - y degrees.
-The measure of the angle adjacent to x is 180 - x degrees.
-You are given that z is 30.
-This means that the other two angles of the triangle should add up to 150 degrees.</p>
<p>-(180 - y) + (180 - x) = 360 - y - x = 150 degrees
-Solve and you end up with -y - x = -210
-S0 x+y = 210.(answer = D)</p>
<p>18)</p>
<p>-You are given that triangle ABD is an isosceles(AB=BC) and angle B is 30 degrees.
-This means that both angle A and C are (180-30)/2 = 75 degrees.(equal angles are opposite equal sides)
-You are given that triangle DEF is an equilateral.
-This means that each of the angles in DEF measure 60 degrees.
-You are given that angle BDE is 50 degrees.
-Since you have the measures of angles BDE and EDF you can now find the measure of angle FDA since they all form a line(180 degrees)
180 - (50+60) = 70 degrees.
-Given FDA(70) and DAF(75) you can now find the measure of DFA.</p>
<p>-180- (70+75) = 35 degrees. (answer = B) </p>
<p>So this means</p>
<p>Thanks for your help, I get them now :D</p>
<p>I know you got a good explanation for the answers to those problems, but I'll try my best to give another good walk-through.</p>
<p>Question 13 (page 683)</p>
<p>The three intersecting lines form a triangle, whose interior angles must have a sum equal to 180 degrees.</p>
<p>We know z = 30, so the other two angles in the triangle must have a sum equal to 150 degrees. Now, all that needs to be done is to determine the other two angles in terms of x and y.</p>
<p>You can easily see that one angle is equal to 180-x, and the other to 180-y.</p>
<p>Now solve.</p>
<p>(180-x) + (180-y) = 150
360 - x - y = 150
-(x+y) = -210
x+y = 210</p>
<hr>
<p>Question 18 (page 586)</p>
<p>We are told that AB = BC and DE=EF=DF, so we know triangle ABC is isocoles and triangle DEF is equilateral (so all of its interior angles are 60 degrees). </p>
<p>If AB = BC in triangle ABC, then angles BAC and ACB are equal. Since we are told angle ABC is equal to 30 degrees, we know that the other two angles must both be equal to 75 to have two identical angles plus an angle of 30 degrees to equal 180 degrees. </p>
<p>Since angle BDE is 50 degrees, and we know angle EDF is 60 degrees, we can solve for angle ADF because they all lie on the same line. </p>
<p>180 = 60 + 50 + ADF
ADF = 70</p>
<p>Now we know two of the interior angles of triangle ADF, so we can solve for the third: angle DFA. </p>
<p>70 + 75 + DFA = 180
145 + DFA = 180
DFA = 35 </p>
<p>Therefore, angle DFA must equal 35 degrees.</p>
<p>Even when I try my best, I fail to see the difference between these solutions and ones in sagarmatha's post #4.
Must be something in the [url=<a href="http://talk.collegeconfidential.com/showthread.php?p=2332112#post2332112%5Dair%5B/url">http://talk.collegeconfidential.com/showthread.php?p=2332112#post2332112]air[/url</a>]. :)</p>
<p>Could I also get help with </p>
<p>Pg. 842 #12</p>
<p>and</p>
<p>Pg. 795 #16</p>
<p>Please
Its 2 more angle problems :( Argh I hate angles <em>)!(@</em>#</p>
<p>bump^ ....</p>
<p>Pg. 842 #12</p>
<p>So for this one you need the formula to find the measure of the interior angles of the triangle. Since this has 4 sides its sum in 360 (# of sides-2)*180. You get 75 for angle CDA. As CDA amd x are supplementary angles substract 75 for 180 and you get 105. </p>
<p>Pg. 795 #16
You see that the three lines from a triangle. You are given the measure of one angle of the triangle as you know its supplementary. You get 65. The other two angles are 180-x and 180-y (as they are supplementary). As these are the measures of a triangle, their sums equal to 180. or 65+180-x+180-y=180. Solve for -x-y and you get
-245. Multiply both sides by a minus 1 and you get 245.</p>