[tex]x^{\circ}=21^{\circ} \ and \ y^{\circ}=39^{\circ}[/tex]
Step-by-step explanation:
We know that vertically opposite angles of a parallelogram are equal .
[tex]\angle ABC =\angle ADC\ and \ \angle BAD = \angle DAC[/tex]
⇒[tex]3x^{\circ}=(4x-21)^{\circ} \ and \ 3y^{\circ}=(y+78)^{\circ}[/tex]
⇒[tex]3x^{\circ}-4x^{\circ}=-21^{\circ} \ and \ 3y^{\circ}-y^{\circ}=78^{\circ}[/tex]
⇒[tex]-x^{\circ}=-21^{\circ} \ and \ 2y^{\circ}=78^{\circ}[/tex]
⇒[tex]x^{\circ}=21^{\circ} \ and \ y^{\circ}=39^{\circ}[/tex]
