EF is tangent to the circle we'll assume; otherwise there's no progress.
Call the center C. ECD is isosceles, formed from two radii and the chord.
Angle CED is complementary to DEF
CED = 90 - 65 = 25 degrees
CDE is congruent, isosceles triangle and all that: CDE=25
That leaves DCE=180-25-25=130 degrees
That's the measure of arc DE as well:
Answer: 130 degrees, choice A
the slope is -12 because y=mx+b and m= slope
The LCM is 540 because 54X10=540 which 20 goes into
