finding a linear diameter

[buc4933]

multiplying pi ¶ (which is equal to 3.14) by the diameter of the circle

 

[buc4933]

right??

 

[bobw]

Yes<br /><br />c = pi X d<br /><br />so you know the circumference ( 3600 light years) and you know pi (3.14159)... how do you figgure out d ? <div class="Discussion_UserSignature"> </div>

 

[buc4933]

11304 final answer right

 

[bobw]

That is only if you are on the other side of the circle from your nova. You are really in the middle. The diameter is the distance across the whole circle. <div class="Discussion_UserSignature"> </div>

 

[buc4933]

then double that answer or.....

 

[bobw]

How did you get 11304 ? <div class="Discussion_UserSignature"> </div>

 

[buc4933]

multiplied 3600 by 3.14

 

[buc4933]

how would I get the final answer

 

[bobw]

if c = pi X d then d does not = c X pi<br /><br />to get d on one side of the equal sign you have to divide both sides by pi<br /><br />c/pi = (pi X d)/pi<br /><br />on the right side pi/pi = 1<br /><br />c/pi = d X 1 ( that's algebra )<br /><br />d = c / pi <div class="Discussion_UserSignature"> </div>

 

[buc4933]

3,600

 

[bobw]

that's c<br /><br /> <div class="Discussion_UserSignature"> </div>

 

[buc4933]

1146.496815

 

[bobw]

1146.496815<br /><br />What is that? radius, diameter, miles? <div class="Discussion_UserSignature"> </div>

 

[buc4933]

diameter

 

[bobw]

So if your star shell is 1 light year angular diameter and you draw lines out to it to make a pie slice shape, where are you? <div class="Discussion_UserSignature"> </div>

 

[buc4933]

I'm guessing i need miles though seeing how it asks for how far away it is

 

[bobw]

if your angular diameter is part of a circle, where is the point of the pie slice in relation to the circle? You should be making drawings on paper to keep your location straight <div class="Discussion_UserSignature"> </div>

 

[buc4933]

I am making drawings but it's not really helping

 

[buc4933]

maybe i'll just move onto the next question, because i feel that i'm not really getting anywhere on this one

 

[yevaud]

http://www.astronomynotes.com/starprop/s2.htm <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[bobw]

UNKNOWN light years would be the length of the vertical line in the center of the triangle below.<br /><br />0.1 degrees is the angle at the top.<br /><br />The diameter of your star shell would be the length of the line on the bottom.<br /><br />The line on the bottom is part of a big circle.<br /><br />Where is the point of the triangle in relation to the big circle?<br /><br /><br /><pre><br /> /|<br /> / | <br /> / | <br />/ | <br />--------- <br /></pre> <div class="Discussion_UserSignature"> </div>

 

[buc4933]

in the middle i guess

 

[bobw]

exactly!<br /><br />so the diameter isn't the answer, is it? <div class="Discussion_UserSignature"> </div>

 

[buc4933]

no its not, but how do I find the answer