Question

$\sf \scriptsize{ABCD \: is \: a \: cylic \: quadrilalteral . \: If \: \angle BCD \: = 100 \degree \: and} \\ \sf \scriptsize{ \: \angle ABD = 70 \degree , find \: ADB}$
​

Answer 1

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

$\huge\boxed{\bf{\red{\fcolorbox{blue}{white}{Answer}}}}$

$\sf \scriptsize\red{Given = } {ABCD \: is \: a \: cyclic \: quadrilateral , \angle \: BCD \: =100° \: and \: \angle ABD = 70°}$

$\sf \scriptsize \red{To \: Find = }{ \angle \: ADB = \: ?}$

$\sf \scriptsize\red{Procedure = }{DCB + DCB = 180 ° ( Opposite \: angles \: of \: Cyclic \: quadrilateral)}$

$\sf \scriptsize{But , \angle \: DCB = 100°} \: \: \: \: \: \: \: \: \: \: \: ...(given)$

$\sf \scriptsize{ \therefore \: \: \angle \: DAB = 180° - 100° = 80°}$

$\sf \scriptsize{Now \: , \angle ADB + \angle \: DAB + \angle \: ABD = 180° \: \: \: \: \: \: .... \: (Sum \: of \: angles \: of \: a \: \triangle \: is \: 180°)}$

$\sf \scriptsize{ \implies \: \angle \: ADB \: + 80 \degree + 70 \degree = 180 \degree} \\ \sf \scriptsize \red{ \angle \: ADB}{ \: = 180 \degree - 150 \degree = 30 \degree.}$

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

$\sf \scriptsize\red{Note = }{Please \: scroll \: from \: left \: to \: right \: side \: to \: } \\ \sf \scriptsize{see \: whole \: Solution \: of \: your \: question. .\: }$

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━