Algebra II › Center and Radius of Circle Functions
A circle is graphed by the equation What is the distance from the center of the circle to the point
on a standard coordinate plane?
What is the center of the circular function ?
Remember that the "shifts" involved with circular functions are sort of like those found in parabolas. When you shift a parabola left or right, you have to think "oppositely". A right shift requires you to subtract from the x-component, and a left one requires you to add. Hence, this circle has no horizontal shift, but does shift 6 upward for the vertical component.
You can also remember the general formula for a circle with center at and a radius of
.
Comparing this to the given equation, we can determine the center point.
The center point is at (0,6) and the circle has a radius of 5.
What is the center and radius of the following equation, respectively?
The equation given represents a circle.
represents the center, and
is the radius.
The center is at:
Set up an equation to solve the radius.
The radius is:
The answer is:
What is the center of this circle: ?
Recall what the standard equation of a circle is:
.
is the center of the circle.
Remember that you have to change the signs!
Thus, since our equation is,
your answer for the center is: .
What is the center of the circle described by ?
Remember that the shifts for circles work in an opposite manner from what you might think. They are like the parabola's x-component. Hence, a subtracted variable actually means a shift up or to the right, for the vertical and horizontal components respectively. Since the x-component has a "+5", it is shifted left 5. Since the y-component has a , it is shifted upward 12. Therefore, this circle has a center at
.
You can also remember the general formula for a circle with center at and a radius of
.
Comparing this to the given equation, we can determine the center point.
The center point is at and the circle has a radius of 6.
What is the center of this circle: ?
First, recall what the standard equation of a circle: . Your center is (h,k). Remember to flip the signs to get your center for this equation:
.
What is the radius of the circle with equation ?
Remember that for the equation of a circle, the lone number to the right of the equals sign is the radius squared.
The general formula for a circle with center at and a radius of
is:
Comparing this to the given equation, we can determine the radius.
The center point is at and the circle has a radius of 9.
What is the sum of the values of the radius and center coordinates (both and
) for the given circle?
Remember that the "shifts" involved with circular functions are sort of like those found in parabolas. When you shift a parabola left or right, you have to think "oppositely". A right shift requires you to subtract from the x-component, and a left one requires you to add. Hence, this circle has a positive 3 horizontal shift, and a negative 2 vertical shift.
You can also remember the general formula for a circle with center at and a radius of
.
Comparing this to the given equation, we can determine the radius and center point.
The center point is at and the circle has a radius of 7.
The question asks us for the sum of these components:
Find the center and radius for the equation:
Write the standard form for the equation of a circle.
The value of is
and the value of
is
. The center of the circle is:
To find the radius, set and solve for
.
Take the square root of both sides. We only consider the positive value since distance cannot be negative.
The answer is:
What is the sum of the values of the radius and center coordinates (both and
) for the given circle?
Remember that the "shifts" involved with circular functions are sort of like those found in parabolas. When you shift a parabola left or right, you have to think "oppositely". A right shift requires you to subtract from the x-component, and a left one requires you to add. Hence, this circle has a negative 5 horizontal shift, and a negative 22 vertical shift.
You can also remember the general formula for a circle with center at and a radius of
.
Comparing this to the given equation, we can determine the radius and center point.
The center point is at and the circle has a radius of 11.
The question asks us for the sum of these components: