\( R_{1}=\left\{(x, y)(x, y \in R) \\\\ x^{2}+y^{2} \leq 25\right\}=R_{1} \) , \( R_{2}=\left\{(x, y) (x, y \in R) \\\\ 9 y \geq 4 x^{2}\right\}=R_{2} \) \( \mathrm{R}_{1} \cap \mathbf{R}_{2} \)