Question

Plzz answer this question from circles

Answer 1

ABCD is a cyclic quadrilateral
sum of opposite angles are supplementary
<D+<B=180
130+<B=180
<B=50
in triangle ABC
<BCA =90 [angle in semicircle=90]
therfore
<CAB+<B+<BCA =180
<CAB+50+90=180
<CAB=180-140=40