Ola Pedro

os pontos

A(3, -9)

B(7, 5)

C(-4, -2)

D(x,y)

Mx = (Ax + Cx)/2 = (3 - 4)/2 = -1/2

My = (Ay + Cy)/2 = (-9 - 2)/2 = -11/2

(Bx + Dx)/2 = -1/2

(7 + Dx) = -1

Dx = -8

(By + Dy)/2 = -11/2

(5 + Dy) = -11

Dy = -16

quarto vértice

D(-8, -16)

pronto