Question

In reperul cartezian xOy se considera puntele A(1,4), B(5,4) si C(5,8). Aratati ca AB este egal cu BC.

Answer 1

$AB=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2} \\\\ AB=\sqrt{(5-1)^2+(4-4)^2}=\sqrt{4^2+0} \\\\ \underline{AB=4} \\\\\\ BC=\sqrt{(5-5)^2+(8-4)^2} \\\\ BC=\sqrt{0+4^2} \\\\ \underline{BC=4} \\\\\ BC=AB=4 \ \ \ c.c.t.d.$