Triangle angle sum theorem and exterior angle theorem
Triangle angle sum theorem and exterior angle theorem
the angle sum of triangle is 180 degrees. it can be explained because all the angle sum is just the number of sides - 2 and multiply them by 180.
and the exterior angle sum of any sides of polygon, including triangle is always 360 degrees
Answer:
5.\(m\angle 1=47^{\circ}\)
\(m\angle 2=137^{\circ}\)
\(m\angle 3=31^{\circ}\)
7.\(m\angle 1=87^{\circ}\)
\(m\angle 2=45^{\circ}\)
\(m\angle 3=45^{\circ}\)
\(m\angle 4=52^{\circ}\)
Step-by-step explanation:
5.\(\angle 1+43^{\circ}+90^{\circ}=180^{\circ}\)
By triangle angle sum theorem
\(\angle +133^{\circ}=180^{\circ}\)
Addition property of integers
\(\angle 1=180-133=47^{\circ}\)
By using subtraction property of equality
\(m\angle 1=47^{\circ}\)
\(m\angle 2=90+47=137^{\circ}\)
By using exterior angle theorem
\(90+47+12+m\angle 3=180^{\circ}\)
By using triangle angle sum theorem
\(149+m\angle 3=180\)
Addition property of integers
\(m\angle 3=180-149=31^{\circ}\)
Using subtraction property of equality
\(m\angle 3=31^{\circ}\)
7.We are given that
\(m\angle ACD=90^{\circ}\)
BC bisects angle ACD
\(m\angle 2=m\angle 3\)
Therefore, \(m\angle 2=\frac{90}{2}=45^{\circ}\)
\(m\angle 2=m\angle 3=45^{\circ}\)
\(m\angle 1+m\angle 2+48=180^{\circ}\)
By using triangle angle sum theorem
Substitute the value
\(45+m\angle 1+48=180\)
\(m\angle 1+93=180\)
By addition property of integers
\(m\angle 1=180-93=87^{\circ}\)
By using subtraction property of equality
\(m\angle 3+m\angle 4+83=180^{\circ}\)
By using triangle angle sum property
Substitute the values
\(45+m\angle 4+83=180\)
\(128+m\angle 4=180\)
Using addition property of integers
\(m\angle 4=180-128=52^{\circ}\)
Using subtraction property of equality