Solve the Problem $z = 5 x ^ { 2 } + 10 y ^ { 2 }$

Multiple Choice

Solve the problem.
-Find the average height of the paraboloid $z = 5 x ^ { 2 } + 10 y ^ { 2 }$ above the annular region $9 \leq x ^ { 2 } + y ^ { 2 } \leq 100$ in the $x y$ -plane.

A) $\frac { 545 } { 2 }$
B) $\frac { 1635 } { 4 }$
C) $\frac { 2725 } { 4 }$
D) 545