Finding the parameters of bivariate Gaussian

Each of the following scenarios describes a joint distribution P(r, y) where r, y E R. In each case, give the parameters of the (unique) bivariate Gaussian that satisfies these properties. (a) x has mean 2 and standard deviation 1, y has mean 2 and standard deviation 0.5, and the correlation between r and y is -0.5. (b) x has mean 1 and standard deviation 1, and y is equal to r