Verified Answer :

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