Answer:
AD = 32
Explanation:
You want the length of side AD of square ABCD, when CD = (x+15) and angle ABC is (6x-12)°.
Value of x
The value of x can be found by recognizing that the measure of any angle in a square is 90°.
(6x -12)° = 90°
6x = 102 . . . . . . . . divide by °, add 12
x = 17
Measure of AD
The sides of a square are congruent, so ...
AD = CD = (x +15) = 17 +15 = 32
The length of AD is 32 units.