Use Pythagorean theorem.
[tex]|ON|^2+|MN|^2=|OM|^2\\\\x^2+x^2=8^2\\\\2x^2=64\ \ \ \ |divide\ both\ sides\ by\ 2\\\\x^2=32\to x=\sqrt{32}\\\\x=\sqrt{16\cdot2}\\\\x=\sqrt{16}\cdot\sqrt2\\\\\boxed{x=4\sqrt2}
Answer: |MN| = 4√2.
80 divided by 6400 is 0.0125, but the question in the picture shows 6400 divided by 80, which is 80.
The next step in the series is choice D.
The answer should be (0, 0).
I'm not sure. Hope it helps.
