Question

In quadilateral ABCD,A:B:C:D=3:4:6:7. Find all the angles of the quadilateral . Hence,prove thhat AB and DC are parallel. Is BC also parallel to AD?

Answer 1

a quadrilateral has its all angle sum=360.
let the angles be 3x,4x,6x,7x.
therefore 3x+4x+6x+7x= 360.
20x=360.
x=18.
so all the angles are 54,72,108,126.
72+108=180.
54+126=180.
as the sum of opposite angles are equal to 180 therefore AB IS PARALLEL TO DC and BC IS PARALLEL TO AD.(HENCE PROVED)