The sum of the four angles of a quadrilateral is 360°
In a quadrilateral ABCD,∠A+∠C=180°, then ∠B+∠D=
360°
180°
80°
100°
Choose the correct option.
By the angle sum property of the quadrilateral.
∠A+∠B+∠C+∠D=360°
we know that the ∠A+∠C=180°
∠B+∠D=360°-180°=180°
Hence, the ∠B+∠C is 180°.
Hence, the correct option is B.
In a cyclic quadrilateral ABCD, ∠ A : ∠ C = 3 : 1 and ∠ B : ∠ D = 1 : 5; find each angle of the quadrilateral.
The angle of a quadrilateral are respectively 100°,98°,92°. The measure of fourth angle is: