Question

The angles A, B, C and D of a quadrilateral ABCD are in the ratio 1 : 3 : 7 : 9, then ABCD is a
Select one:
a. Trapezium with BC || AD
b. Trapezium with AB || CD
c. Parallelogram

Answer 1

Step-by-step explanation:

) Given, ratio of angles of quadrilateral ABCD is 1 : 3 : 7 : 9

Let angles of quadrilateral ABCD be ∠A:∠B:∠C:∠D= 1x:3x: 7x : 9x, respectively. We know that, sum of all angles of a quadrilateral is 360°.

1x + 3x + 7x + 9x = 360°

=> 20x = 360°

=> x=360°/20° = 18°

=>∠A= 1x= 1×18 =18°

=>∠B= 3x =3×18= 54°

=>∠C=7x=7×18=126°

=>∠D=9x= 9×18= 162°

option B is correct ans