7. The distance from the center of circle $C : x ^ { 2 } + y ^ { 2 } - 2 x - 4 y + 4 = 0$ to the line $3 x + 4 y + 4 = 0$ is $d =$ $\_\_\_\_$.
(5 points) A rectangular parallelepiped has length, width, and height of $2 a , a , a$ respectively. All its vertices lie on a sphere. Then the surface area of the sphere is
7. The distance from the center of circle $C : x ^ { 2 } + y ^ { 2 } - 2 x - 4 y + 4 = 0$ to the line $3 x + 4 y + 4 = 0$ is $d =$ $\_\_\_\_$.\\