\(y=mx+c\)...\[y-y_1=m(x-x_1)\]...\[ax+by+c=0\]

\[\sqrt{(x_2-x_1)^2 + (y_2-y_1)^2}\]

\[(\frac{x_1+x_2}{2} , \frac{y_1+y_2}{2})\]

\[\frac{y_2-y_1}{x_2-x_1}\]

\[\frac{1}{2}.b.h\]

\[\frac{1}{2} | x_1.y_2 - x_2.y_1 |\]

\[d=\frac{ | ax_1+by_1+c | }{\sqrt{a^2+b^2}}\]

\[c=(\frac{hx_2+kx_1}{h+k} , \frac{hy_1+ky_2}{h+k})\]

\[(\frac{x_1+x_2+x_3}{3}),(\frac{y_1+y_2+y_3}{3})\]