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2009 AMC 12B Question 23

AMC12 · 2009 AMC 12B

Question 23

A region $S$ in the complex plane is defined by $$
\scriptsize S = \{x + iy : -1 \le x \le 1,\ -1 \le y \le 1\}.
$$

A complex number $z = x + iy$ is chosen uniformly at random from $S.$ What is the probability that $\left(\dfrac{3}{4} + \dfrac{3}{4}i\right)z$ is also in $S?$
  1. $\dfrac{1}{2}$
  2. $\dfrac{2}{3}$
  3. $\dfrac{3}{4}$
  4. $\dfrac{7}{9}$
  5. $\dfrac{7}{8}$