Answer:
C.) 4
Explanation:
we are given ABCD is an isosceles trapezoid
AB || CD
AB = m + 6
CD = 3m + 2
BC = 3m
AD = 7m - 16
Since, ABCD is an isosceles trapezoid
so, two sides must be equal

now, we can plug values

now, we can solve for m


Divide both sides by -4
and we get
