The answer is D. 42
A triangle equals 180 in total so what you would do it subtract 122 from 180 because 180 is also the angle of a straight line. You would get 58 then you add 58 and 80 to get 138. Subtract 138 from 180 and you get your answer of 42
Answer:
An angle bisector is a line passing through the vertex of the angle that cuts the angle into two equal smaller angles.
Given: MN is angle bisector,
then
....... [1]
Congruent angles are two or more angles that have the same measure.
then;
by definition of congruent angles
[1]⇒
......[2]
By the Angle addition postulates states that if M is in the interior of ∠JMK then,
......[3]
Now, by substitution property ; substitute the equation [2] in [3] we get;
......[4]
Like terms terms whose variables are the same
Combine like terms in equation [4] we get
......[5]
Division property of equality states that you divide the same number to both sides of an equation.
Divide by 2 to both sides in equation [5] , we get
Volume =πr²*h=π*7²*4=196π
answer B