Question:
What is the distance between the points A (c, 0) and B (0, −c)?
Solution:
We have to find the distance between $\mathrm{A}(c, 0)$ and $\mathrm{B}(0,-c)$.
In general, the distance between $\mathrm{A}\left(x_{1}, y_{1}\right)$ and $\mathrm{B}\left(x_{2}, y_{2}\right)$ is given by,
$\mathrm{AB}=\sqrt{\left(x_{2}-x_{1}\right)^{2}+\left(y_{2}-y_{1}\right)^{2}}$
So,
$\mathrm{AB}=\sqrt{(c-0)^{2}+(0-c)^{2}}$
$=c \sqrt{2}$