Based on the given information, determine which sides of quadrilateral abcd must be parallel. angle a=67 b=120 c=73 d=100

You have given quadrilateral ABCD with angles m∠A=67°, m∠B=73°, m∠C=120° and m∠D=100°.

m∠A+m∠B=140°,

m∠A+m∠C=187°,

m∠A+m∠D=167°,

m∠B+m∠C=193°,

m∠B+m∠D=173°,

m∠C+m∠D=220°.

If two lines cut by a transversal have supplementary consecutive interior angles (that together form 180°), then the lines are parallel. From the sums above you see that there aren't two quadrilateral angles which form together 180°, so you can conclude that no sides of the quadrilateral are parallel.