Question

Quadrilateral ABCD is inscribed in circle O.

What is ​ m∠B ​ ?




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Answer 1

I encourage everyone taking this test to take my word that it's 125.

Answer 2

Opposite angle of a quadrilateral add up to 180 degrees.

This means Angle A plus Angle C equal 180.

We can solve for X using that, then solve for Angle B.

2x-7 + x +4 = 180

Simplify:

3x -3 = 180

Add 3 to each side:

3x = 183

Divide both sides by 3:

x = 183 /3

x = 61

Now we know x, replace x with 61 in the equation for Angle B:

Angle B = 2x+3 = 2(61) +3 = 122 +3 = 125 degrees.