M_6 is (2x – 5)º and m_8 is (x + 5)º. What is m 3?

Q: I can’t seem to figure out the equation. Could someone explain step by step and give a link to a video like Kahn Academy to explain? I’m lost !

m_6 + m_8 = 180º because they form a straight line.

So, (2x-5) + (x+5) = 180

    3x = 180

      x = 60

So, m_115º    (2•60 - 5 = 115)

Also, because the two lines are parallel m_6 = m_3 by alternate interior angles.

So, m_3 = 115º

answer: option a.

step-by-step explanation:

you know that the quadrilateral opqr ( a four sided figure) is inscribed in circle. this means that all its vertices are on the circle.

then, by definition, the opposite angles of the quadrilateral are supplementary, this means that the sum of their measures is 180 degrees.

you can observe in the figure that the angles ∠opq   and the angle ∠orq   are opposite, therefore:

then, can be used to d to calculate the measure of ∠opq