Question

​ HELPP.

Answer 1

Answer:  $m\angle{B}=132^{\circ}$

Step-by-step explanation:

In the given picture, we have given cyclic Quadrilateral ABCD ​which is inscribed in this circle.

We know that in cyclic quadrilateral the sum of the opposite angles is equals to $180^{\circ}$

According to the given picture we have ,

$m\angle{D}+m\angle{B}=180^{\circ}\\\\\Rightarrow x+(3x-12)=180\\\\\Rightarrow x+3x-12=180\\\\\Rightarrow 4x=180+12\\\\\Rightarrow 4x=192\\\\\Rightarrow x=48$

Therefore, $m\angle{B}=(3(48)-12)^{\circ}=132^{\circ}$

Answer 2

The measure of angle B is 132 degrees.  A quadrilateral must add up to 360 degrees.  You are given x and 3x-12.  Half of a square's angles is 180.  4x-12 = 180 which x = 48.

Finally, you plug x in for 3x-12 and you get 132 degrees for B.

This assumes that DC and AB are of the same length