Points A (-3, -2), B (-6, a), C (-3, -4) and D(0, -1) are the vertices of quadrilateral ABCD; find a if 'a' is negative and AB = CD.

Given: Points A(-3, -2), B(-6, a), C(-3, -4) and D(0, -1) are the vertices of quadrilateral ABCD and AB = CD. Distance between the given points = Distance between points A(-3, -2) and B(-6, a): Distance between points C (-3, -4) and D(0, -1): Since AB = CD, Since it is given that a is negative, we select a = -5. Hence, the value of a = -5.