Question 11 Mark
In cyclic quadrilateral ABCD $m\angle A=100^{\circ}$, then find $m\angle C$.
Answer
View full question & answer→Opposite angles of a cyclic quadrilateral are supplementary.
$m\angle A + m\angle C = 180^{\circ}$
$100^{\circ} + m\angle C = 180^{\circ}$
$m\angle C = 180^{\circ} - 100^{\circ} = 80^{\circ}$
$m\angle A + m\angle C = 180^{\circ}$
$100^{\circ} + m\angle C = 180^{\circ}$
$m\angle C = 180^{\circ} - 100^{\circ} = 80^{\circ}$