if you are looking for.... 2(B-4)= (6)b
2b - 8 = 6b
2b - 6b= 8
-4b=8
so b= -2
the question is b-4 divided by 6 equals b/2
90. The measure of an inscribed angle is half of that of the measure of its arc, and the measure of the angle corresponding with arc a is 45. 45*2 is 90, so 90 is the measure of arc a.