Question -
Answer -
In quadrilateral ABCD, AB || DC and AD || BC and тИаA = 60┬░
┬а
тИ╡ AD || BC and AB || DC
тИ┤ ABCD is a parallelogram
тИ┤ тИаA + тИаB = 180┬░ (Co-interior angles)
60┬░ + тИаB = 180┬░
тЗТ тИаB = 180┬░-60┬░= 120┬░
But тИаA = тИаC and тИаB = тИаD (Opposite angles of a ||gm)
тИ┤ тИаC = 60┬░ and тИаD = 120┬░
Hence тИаB = 120┬░, тИаC = 60┬░ and тИаD = 120┬░