Which of the following is not a property of quadrilaterals? . a.. there are four sides.. b.. there are four diagonals.. c.. there are four vertices.. d.. the measures of the interior angles add up to 360.

The correct answer for this question is letter "(B) There are four diagonals." It is not a property of quadrilaterals. Among the properties of quadrilaterals include (1) There are four sides, (2) There are four vertices, (3) The measures of the interior angles add up to 360.

In the first triangle 80+20+p=180 (since sum of all angles of a triangle is 180)so p= 80also in second triangle 55+45+q=180 (since sum of all angles of a triangle is 180)so q=80so we can conclude that p=80 degrees q=80 degrees so p=q=80 degreeshence option b is correct

X=y+4 is the answe