Answer:
75 degrees
Explanation:
since this figure has four sides we can figure out the measure of the interior angles by using the formula, (n-2)*180, where 'n' = number of sides
(4-2)180 = 2(180) = 360
also, we know that since AB is parallel to DC that the figure is a rhombus where adjacent angles are supplementary
therefore, we can find 'x' by writing this equation:
12x - 3 + 9x - 6 = 180
simplify:
21x - 9 = 180
21x = 189
x = 9
also, we know that opposite angles in a rhombus are equal so if we substitute '9' for 'x' in angle C we will know the measure of angle A:
m<A = 9(9)-6
m<A = 81-6
m<A = 75 degrees