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Find the measure of each angle in triangle ABC. Triangle A B C has angles labeled as follows: A, (x minus 16) degrees; B, (2x minus 155) degrees; C, (one half x plus 8) degrees. left parenthesis 2 x minus 155 right parenthesis degrees(2x−155)° left parenthesis one half x plus 8 right parenthesis degrees12x+8° left parenthesis x minus 16 right parenthesis degrees(x−16)° ABC

 

The measure of angle A is

The measure of angle B is 

The Measure of angle C is 

 

ladiikeiii  Dec 1, 2017

Best Answer 

 #1
avatar+1493 
+2

The triangle sum theorem states that the sum of the measures of the interior angles of a triangle equals 180 degrees. Using this theorem alone, one can find the measure of all the angles.

 

\(m\angle A+m\angle B+m\angle C=180\) Plug in the measure for all these angles by using substitution.
\(x-16+2x-155+\frac{1}{2}x+8=180\) Combine like terms.
\(3x+\frac{1}{2}x-163=180\) Add 163 to both sides.
\(\frac{6}{2}x+\frac{1}{2}x=343\) Meanwhile, I converted 3x to a fraction that I can combine with the other lingering fraction.
\(\frac{7}{2}x=343\) Multiply by 2 on both sides.
\(7x=686\) Divide by 7 on both sides.
\(x=98\)  
   

 

Now, plug in this value for the angle measure expressions.

 

\(m\angle A=x-16=98-16=82^{\circ}\)

\(m\angle B=2x-155=2*98-155=196-155=41^{\circ}\)

\(m\angle C=\frac{1}{2}x+8=\frac{1}{2}*98+8=49+8=57^{\circ}\)

TheXSquaredFactor  Dec 1, 2017
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1+0 Answers

 #1
avatar+1493 
+2
Best Answer

The triangle sum theorem states that the sum of the measures of the interior angles of a triangle equals 180 degrees. Using this theorem alone, one can find the measure of all the angles.

 

\(m\angle A+m\angle B+m\angle C=180\) Plug in the measure for all these angles by using substitution.
\(x-16+2x-155+\frac{1}{2}x+8=180\) Combine like terms.
\(3x+\frac{1}{2}x-163=180\) Add 163 to both sides.
\(\frac{6}{2}x+\frac{1}{2}x=343\) Meanwhile, I converted 3x to a fraction that I can combine with the other lingering fraction.
\(\frac{7}{2}x=343\) Multiply by 2 on both sides.
\(7x=686\) Divide by 7 on both sides.
\(x=98\)  
   

 

Now, plug in this value for the angle measure expressions.

 

\(m\angle A=x-16=98-16=82^{\circ}\)

\(m\angle B=2x-155=2*98-155=196-155=41^{\circ}\)

\(m\angle C=\frac{1}{2}x+8=\frac{1}{2}*98+8=49+8=57^{\circ}\)

TheXSquaredFactor  Dec 1, 2017

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