Question

The angles of a quadrilateral are in A.P with common difference 20degree ( mention degree in symbol). find its angle.​

Answer 1

let the quadrilateral be ABCD

the angles are in AP ....given

let angle A be a

hence angle B = 20+a

angle C= 20 + 20+x =40+a

angle D= 40+ 20+x=60+a

angles(A+B+C+D)=360°

a+20+a+40+a+60+a=360°

4a+120=360

4a=360-120

4a=240

a=60

hence,

angle A=60

angle B=80

angle C=100

angle D= 120

hope this helps.

Answer 2

Step-by-step explanation:

d=20

n=4

sn=n/2{2a+(n-1)d}

360°=2{2a+(3)20°}

360°/2={2a+60°}

180°-60°=2a

120°=2a

60°=a

a1=60°

a2=80°

a3=100°

a4=120°

Hope it will help u....