Q9: The measure of ∠A is half the difference of the intercepted arcs. .. (55 -12)/2 = 21.5
Q10: Tangents from the same point are congruent. .. x +15 = 2x -5 .. 20 = x
Q7: The given congruences let you write two equations. .. -x = y +8 .. -x = 3y +16 Equating the two equations for -x and solving for y gives .. 3y +16 = y +8 .. 2y = -8 .. y = -4 .. -x = -4 +8 = 4 .. x = -4
Q8: The angle at the intersection is half the sum of the intercepted arcs. (Compare to Q9, where the intersection is external to the circle.) .. 110 = (97 +x)/2 .. x = 220 -97 = 123
