(30 points!)
determine which lines are parallel??

looks like the parallel lines are "l" and "n"

Step-by-step explanation:

when two lines are parallel, they should be across from each other going the same way. For example: / / , or \ \  sometimes even on top of each other. It can't be line "m" because it seems a little slanted. Parallel lines have to be the same length and same size. It can't be line "t" because the line is going in a different direction.

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