<p>hey all i came across the question on the college board's offical test prep booklet. wasnt able to answer it. would appreciate some help and fast.</p>
<p>What is the measure of one of the larger angles of a parallelogram in the xy plane that has vertices with co-ordinates (2,1),(5,1),(3,5) and(6,5)?</p>
<p>A)93.4 degrees
B)96.8 degrees
C)104 degrees
D)108.3 degrees
E)119 degrees.</p>
<p>Bump!!!!!!!!!</p>
<p>104</p>
<p>180-tan^-1(4)</p>
<p>I would really appreciate an explanation as to how u came up with that answer..</p>
<p>Draw the parallelogram. You will notice that the angle formed by the intersection of 2 lines at (3,5) is a larger angle. Notice that you can create a right triangle to determine the supplement of that angle (leg lengths would be 1 and 4) To determine the angle of the supplement, you need to find tan^-1 (4/1) = 76 degrees. The larger angle must be 180-76 = 104 degrees.</p>
<p>umm.. im sorry but i still didnt get that!!!! how do u get the legs to be 4 and 1 and then how is the learger angle 180-76..??</p>
<p>Pick any point. Find the angle through simple trigonometry (formation of a right triangle, formation of a regular triangle and law of cosines, etc.)</p>
<p>if the angle times 2>180 then it is the larger angle. </p>
<p>if not, (360-(the angle times 2))/2 will give you larger angle.</p>
<p>edit:
some important stuff you should already know
1) The sum of the interior angles of a parallelogram is 360.
2) Opposite angles of a parallelogram are equal.
3) How to form a right triangle and use simple right triangle trigonometric ratios.</p>
<p>barron's had this complicated equation using slopes of the lines and stuff. but this seems so much more easier. dang barrons.</p>