28. Five mark exercise problems VI

$ABCD$ is a cyclic quadrilateral such that $\angle A = (4y + 20)^{\circ}$, $\angle B = (3y - 5)^{\circ}$, $\angle C = (4x)^{\circ}$ and $\angle D = (7x + 5)^{\circ}$. Find the four angles.

 

Answer:

 

$\angle A =$ $i\mathrm{°}$

 

$\angle B =$ $i\mathrm{°}$

 

$\angle C =$ $i\mathrm{°}$

 

$\angle D =$ $i\mathrm{°}$