Fill in the blanks.
The standard form for a circle is useful because we can see the
?
area and circumference
center and radius
diameter and arclength
of the circle in the equation.
A quadratic equation in two variables describes a circle if the coefficients of the quadratic terms are
?
squared
opposites
equal
zero
.
We convert the equation for a circle into standard form by
?
completing the square
cross-multiplying
factoring
in both variables.