A cyclic quadrilateral is a quadrilateral whose vertices all touch the circumference of a circle.
Opposite angles in a cyclic quadrilateral add to 180 degrees. Quadrilateral ABCD is a cyclic quadrilateral.
< A+<C=180
Substituting <A and <B values given in figure:
x+2+x-2=180
Adding like terms:
2x=180
Dividing both sides by 2
x=90°
<A=x+2=90+2=92°
<C=x-2=90-2=88°
<D=x-10=90-10=80°
<B+<D=180
<B=180-80=100°
The angles of the quadrilateral ABCD are
<A=92°
<B=100°
<C=88°
<D=80°
