ABCD is a cyclic quadrilateral such that ∠A=(4y+20)∘,∠B=(3y−5)∘,∠C=(4x)∘and∠D=(7x+5)∘. Find the four angles.
In a cyclic quad , sum of opposite angles is 180
A +C=180∘
4y+20+4x=180∘
4y+4x=160∘
x+y=40∘ ---- (i)
B + D =180∘
3y−5+7x+5=180∘
7x+3y=180∘ ----(ii)
(ii)-3(i)
4x=60
x=15
y=25
A=120∘B=70∘C=60∘D=110∘