Question

in a cyclic quadrilateral ABCD angle a - angle c = 20. find angle a. ​

Answer 1

Sum of two opposite angles of quadrilateral is 180.

So,angle a+angle c=180 ......(1)

angle a -angle c=20.........(2)

From (1).......angle a=180-angle c

Put it in (2).....

180-angle c-angle c=20

180-20=2angle c

160/2=angle c

angle c=80

angle a +angle c=180

angle a =100