`A B C D` is a cyclic trapezium with `A D B Cdot` If `/_B=70^0,` determine other three angles of the trapezium.

Explanation

`A B C D`is a cyclic trapezium with `A D || BCdot`
`/_A+/_B=180^0`(Sum of cointerior angles)
`/_A+70^0=180^0`
`/_A=180^0-70^0=110^0`
`/_A+/_C=180^0,/_B+/_D=180^0`
(Sum of opposite angles of a cyclic quadriteral)
`110^0+/_c=180^0`
`/_C=180^0-110^0=70^0`
`/_70^0+/_D=180^0`
`/_D=180^0-70^0=110^0`
`/_A=110^0,/_C=110^0 \and\ /_D=/_110^0`