The figure attached has <DEF which is an inscribed angle. An inscribed angle is an angle with its vertex on the circle which is formed by two intersecting chords. According to formulas, the measurement of arc DF is twice the measurement of ∡DEF. Arc DF is equal to 360-248 or 112. Hence <span>∡DEF is equal to 56 degrees.</span>
Point A ( -1/2,1/4)
Point B (-2 1/2,-1 1/2)
Point C (1/2,1/4)
We can employ some logic to reduce the answers we need to test. We know that the slope perpendicular to line l has to have a negative reciprocal slope, so a slope of
. We see that in A and C, as x increases so does y. That means the slope of these equations are positive, which we don't want. Now for some algebra:

We se that D has the correct slope so that must be the answer.