Question

Which of the following could be points on the unit circle?

Answer 1

Answer:

A and D

Step-by-step explanation:

Unit circle is a circle described by the equation

x^2 + y^2 = 1

We can try each pair and check

A. $(\frac{6}{7})^2 + (\frac{\sqrt{13}}{7})^2 = \frac{36}{49} + \frac{13}{49} = \frac{49}{49} = 1$

B. $(\frac{4}{3})^2 + (\frac{4}{5})^2 > (\frac{4}{3})^2 > 1$

C. $(\frac{1}{3})^2 + (\frac{2}{3})^2 = \frac{1}{9} + \frac{4}{9} = \frac{5}{9} < 1$

D. $(\frac{5}{13})^2 + (\frac{12}{13})^2 = \frac{25}{169} + \frac{144}{169} = \frac{169}{169} = 1$