I believe by m you are solving for angle F. So, angle H =71 degrees. GF and HI are parallel. In order to find angle G, Take the supplementary of 71 degrees, so 180-71 = angle G =109 degrees. Because GH and FI are congruent, the angles should be same across the shape, so angle I 71 degrees. Quadrilateral has a total of 360 degrees, so, 360-71-109-71=109 degrees. In general, angke G would equal angle F because of the trapezoid properties that take place when both bases are parallel and two of the sides are congruent, the trapezoid is an isosceles trapezoid
