KöMaL 2011 K298

Three consecutive sides of a quadrilateral have the same length. The two interior angles enclosed by the three sides are $60^o$ and $70^o$. What is the measure of the largest angleThree consecutive sides of a quadrilateral have the same length. The two interior angles enclosed by the three sides are $60^o$ and $70^o$. What is the measure of the largest angle of the quadrilateral? of the quadrilateral?