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Seven points are evenly spaced out on a circle and connected as shown below to form a 7-pointed star. What is the sum of the angle measurements of the seven tips of the star, in degrees? One such angle is marked as a below.

waffles  Oct 14, 2017
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6+0 Answers

 #1
avatar+91027 
0

Where is the pic??

Melody  Oct 15, 2017
 #2
avatar+91027 
+2

This is what I am imagining that you mean:

The answer is aprroximately (maybe exactly)   540 degrees  

 

 

Melody  Oct 16, 2017
 #6
avatar+91027 
+3

Looking at my picure I just thought of a much better way to do this :

 

 

I can see that the dark green arc is  3/7 of the circle.

So the angle at the centre that issubtend by this arc must be    \(\frac{3}{7}*360=\frac{3*360}{7}\)

 

Now a very commonly used circle property is that the angle at the centre subtended by an arc is twice the angle at the circumference subtended by the same arc.

so the angle at the circumference, which is one of the points of the star must be   \(\dfrac{1}{2}*\dfrac{3*360}{7}=\dfrac{3*360}{2*7}\)

 

So the angle sum of all points of the star is   \(7*\dfrac{3*360}{2*7}=\dfrac{3*360}{2}=3*180=540^\circ\)

 

 

Melody  Oct 17, 2017
 #3
avatar+387 
+1

yes you got the picture right

waffles  Oct 16, 2017
 #4
avatar+78632 
+1

Nice detective work, Melody.........!!!!

 

 

 

cool cool cool

CPhill  Oct 16, 2017
 #5
avatar+91027 
+1

Thanks Chris :)

and

thanks Waffles too :)

Melody  Oct 16, 2017

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