Let ABCD be the given quarillateral and let `angle A =(3x)^(@), angle B =(5x)^(@), angle C =(9x)^(@) and angle D = (13x)^(@).` Since the sum of the angles of a quadrilateral is `360^(@)`, we have `3x+5x+9x+13x=360 rArr 30x=360 rArr x = 12.` `therefore angle A = 36^(@), angle B=60^(@), angle C= 108^(@) and angle D= 156^(@).`