Quadrilateral ABCD is inscribed in a circle.
What is the measure of angle A?

Enter your answer in the box.

m∠A= [ ]°

flanspawn  May 11, 2018

The figure ABCD has four sides, and its vertices lie on a circle. This situation has a specific name: cyclic quadrilateral. This situation also has a specific theorem associated to it: Opposite angles of a cyclic quadrilateral are supplementary. Let's use this theorem to our advantage:


\(m\angle A+m\angle C=180^{\circ}\) Substitute in the known expressions for both of these angles. 
\(3x+6+x+2=180\) Now, simplify the left-hand side as much as possible.
\(4x+8=180\) Now, use algebraic manipulation to isolate the variable. 
\(x=43\) Now, find the measure of the missing angle.
\(m\angle A=3x+6\) Substitute in the known value for x. 
\(m\angle A=3*43+6\) Simplify.
\(m\angle A=135^{\circ}\)  


TheXSquaredFactor  May 11, 2018

11 Online Users


New Privacy Policy

We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive information about your use of our website.
For more information: our cookie policy and privacy policy.