[math] \newcommand{\ex}[1]{\item } \newcommand{\sx}{\item} \newcommand{\x}{\sx} \newcommand{\sxlab}[1]{} \newcommand{\xlab}{\sxlab} \newcommand{\prov}[1] {\quad #1} \newcommand{\provx}[1] {\quad \mbox{#1}} \newcommand{\intext}[1]{\quad \mbox{#1} \quad} \newcommand{\R}{\mathrm{\bf R}} \newcommand{\Q}{\mathrm{\bf Q}} \newcommand{\Z}{\mathrm{\bf Z}} \newcommand{\C}{\mathrm{\bf C}} \newcommand{\dt}{\textbf} \newcommand{\goesto}{\rightarrow} \newcommand{\ddxof}[1]{\frac{d #1}{d x}} \newcommand{\ddx}{\frac{d}{dx}} \newcommand{\ddt}{\frac{d}{dt}} \newcommand{\dydx}{\ddxof y} \newcommand{\nxder}[3]{\frac{d^{#1}{#2}}{d{#3}^{#1}}} \newcommand{\deriv}[2]{\frac{d^{#1}{#2}}{dx^{#1}}} \newcommand{\dist}{\mathrm{distance}} \newcommand{\arccot}{\mathrm{arccot\:}} \newcommand{\arccsc}{\mathrm{arccsc\:}} \newcommand{\arcsec}{\mathrm{arcsec\:}} \newcommand{\arctanh}{\mathrm{arctanh\:}} \newcommand{\arcsinh}{\mathrm{arcsinh\:}} \newcommand{\arccosh}{\mathrm{arccosh\:}} \newcommand{\sech}{\mathrm{sech\:}} \newcommand{\csch}{\mathrm{csch\:}} \newcommand{\conj}[1]{\overline{#1}} \newcommand{\mathds}{\mathbb} [/math]

Write an equation for each of the following.

• A circle with center at the origin and radius [math]3[/math].
• A circle with center at the origin and radius [math]\frac{10}3[/math].
• A circle with center at [math](-2, 2)[/math] and radius [math]5[/math].
• A circle with center at [math](3, 0)[/math] and radius [math]3[/math].
• A circle with center at [math](0, -7)[/math] and radius [math]7[/math].
• A circle with center at [math](-3, -3)[/math] and radius [math]3\sqrt2[/math].
• A circle with center in the first quadrant, radius [math]4[/math], and tangent to both axes.
• A circle with center on the [math]y[/math]-axis, radius [math]\frac52[/math], and tangent to the [math]x[/math]-axis (there are two such circles).
• A circle with radius [math]2[/math] and tangent to the [math]x[/math]-axis and to the line defined by the equation [math]x=5[/math] (there are four such circles).