3.What is the sum of the measures of the angles of a convex quadrilateral? Will this property hold if the quadrilateral is not convex? (Make a non-convex quadrilateral and j try!)

The sum of measures of the angles of a convex quadrilateral is \(\360^{\circ}\) because it is made up of two triangles and the sum of internal angle of convex quadrilateral is equal to the sum of interior angles of two triangles i.e, \(\360^{\circ}\).Yes, this property holds in case if the quadrilateral is not convex.