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What is the interior degree measure of angle A?

 May 1, 2023
 #2
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What is the interior degree measure of angle A?   

 

We're going to use three mathematical facts. 

 

1.  A straight line is 180o  

2.  The interior angles of a triangle total 180o  

3.  Vertical angles are equal.  

 

Start with the triangle at the bottom left.  

It already has 40o showing. The other side of the 110o is 70o.  

40o plus 70o is 110o so the angle at the top left of that triangle is 70o.  

 

Next, the triangle at the top left.  

The vertical angle of the 70o is 70o.  The other side of the 110o is 70o.  

70o plus 70o is 140o so the angle labled A = 40o.   

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 May 1, 2023
 #3
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CORRECTION TO THE ABOVE  

 

CHANGE THIS PARAGRAPH

 

Next, the triangle at the top left.

The vertical angle of the 70o is 70o.  The other side of the 110o is 70o.

70o plus 70o is 140o so the angle labled A = 40o

 

TO THIS PARAGRAPH: 

 

Next, the triangle at the top left.  

The vertical angle of the 70o is 70o.  The other side of the 100o is 80o.  

70o plus 80o is 150o so the angle labled A = 30o

 

A silly typo.  The bad part is, I checked it several times before I posted it. 

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Guest May 2, 2023
 #4
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thank you guest!

Keihaku  May 2, 2023
edited by Keihaku  May 2, 2023

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