I feel like I should be understanding these, but just can't make any headway:

1) If X~gamma(alpha, theta), then show that cX~gamma(alpha, theta/c).

and

2) If X1, X2, ..., Xn are independent and ~Normal(mu, sigma^2), show that (1/sigma^2)(X1^2 + X2^2 + ... + Xn^2)~gamma(n/2, 1/2).

Any suggestions or help much appreciated.