Leiame punkti C koordinaadid ja kolmnurga ABC pindala:

$$C = A + \vec{AC} = (2; -4) + (4; 3) = (6; -1)$$ $$\vec{AB} = B - A = (3; 1) - (2; -4) = (1; 5)$$ $$\vec{BC} = C - B = (6; -1) - (3; 1) = (3; -2)$$ $$\vert{\vec{AB}}\vert = \sqrt{1^2 + 5^2} = \sqrt{26}$$ $$\vert{\vec{BC}}\vert = \sqrt{3^2 + (-2)^2} = \sqrt{13}$$ $$\vert{\vec{AC}}\vert = \sqrt{4^2 + 3^2} = 5$$ $$S = \sqrt{p(p-a)(p-b)(p-c)}$$ $$p = \frac{a + b + c}{2}$$ $$p = \frac{\sqrt{26} + \sqrt{13} + 5}{2}$$ $$S = 8.5$$

Leiame sirge võrrandi ja tõusu:

Punkti D koordinaadid on $$(2; -\frac{3}{2})$$ $$\frac{x- 2}{6 - 2}=\frac{y + \frac{3}{2}}{-1 - (-\frac{3}{2})}$$ $$y = \frac{1}{2}x - \frac{5}{2}$$ $$k = \frac{1}{2}$$