Answer
Elliptical (circular) cone.
See image:
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Work Step by Step
Comparing to Table 11.1, the equation is of the form
$\displaystyle \frac{x^{2}}{1^{2}}+\frac{y^{2}}{1^{2}}=\frac{z^{2}}{1}$
this is an elliptical cone, in which the traces in planes parallel to the xy plane ( $z=k$) are circles of radius $k$.
