Leiame punkti B ja C koordinaadid ning kolmnurga pindala:

$$B = A + \vec{AB} = (1; 2) + (4; -3) = (5; -1)$$ $$C = A + \vec{AC} = (1; 2) + (1; 6) = (2; 8)$$ $$\vec{BC} = C - B = (2; 8) - (5; -1) = (-3; 9)$$ $$\vert{\vec{AB}}\vert = \sqrt{4^2 + (-3)^2} = \sqrt{16 + 9} = \sqrt{25} = 5$$ $$\vert{\vec{AC}}\vert = \sqrt{1^2 + 6^2} = \sqrt{1 + 36} = \sqrt{37}$$ $$\vert{\vec{BC}}\vert = \sqrt{(-3)^2 + 9^2} = 3\sqrt{10}$$ $$S = \sqrt{p(p-a)(p-b)(p-c)}$$ $$p = \frac{a + b + c}{2}$$ $$p = \frac{5 + \sqrt{37} + 3\sqrt{10}}{2}$$ $$S = 13.5$$

Leiame sirge tõusu:

$$k_1 k_2 = -1$$ $$k_1 = \frac{3}{2}$$ $$k_2 = -\frac{2}{3}$$

Leiame punkti D koordinaadid:

$$y=kx+b$$ $$-1 = 5k + b$$ $$8 = 2k + b$$ $$-1 - 5k = 8 - 2k$$ $$k = -3$$ $$b = 14$$ $$y = -3k + 14$$ $$D(4; 2)$$

Leiame sirge võrrandi:

$$y=-\frac{2}{3}x+b$$ $$2 = -\frac{8}{3} + b$$ $$b = \frac{6}{3} + \frac{8}{3} = \frac{14}{3}$$ $$y = -\frac{2}{3}x + \frac{14}{3}$$