Show that the points A(2,-2), B(14, 10), C(11, 13) and D(-2, 1) are the vertices of reclangle

  is not a rectangle

Step-by-step explanation:

The midpoints of the diagonals are ...

  AC midpoint = ((2, -2) +(11, 13))/2 = (13/2, 11/2)

  BD midpoint = ((14, 10) +(-2, 1))/2 = (6, 11/2)

The midpoints of the diagonals are different, so this is not a rectangle or any sort of parallelogram.

the answer is (-8,-5)

step-by-step explanation:

the endpoint to midpoint is half the length. the length is (-2,-1) so when you are at the midpoint just add it to it to find your answer -6+(-2)= -8 and -4+(-1)=-5 so (-8,-5)

arc length = radius * x ( in radians)

6 * pi = 18 * x

divide by 18 on each side

6 pi / 18 = x

pi/3 = x

the angle is pi / 3 radians

or   60 degrees