Let
\[
A_{1}=\left\{(x, y):|x| \leqslant y^{2},|x|+2 y \leqslant 8\right\} \text { and }
\]
\( A_{2}=\{(x, y):|x|+|y| \leqslant k \} \). If \( 27\left(\right. \) Area \( \left.A_{1}\right)=5\left(\right. \) Area \( \left.A_{2}\right) \), then \( k \) is equal to :