Find the circumference of the circle defined as follows :
\left(x+2\right)^2+\left(y-2\right)^2=9
The circumference of a circle with radius r equals:
2\pi r
The equation of a circle has the form:
\left(x-h\right)^2+\left(y-k\right)=r^2
So we have r=3.
Therefore, the circumference of this circle is:
2\pi \times 3 = 6\pi
The circumference of the circle is 6\pi.
Find the area of the following circle:
The area of a circle with radius r equals:
\pi r^2
According to the graph, the radius of the circle is 3. Therefore, the area of this circle is:
\pi \times 3^2 = 9\pi
The circumference of the circle is 9\pi.
Find the circumference of the following circle:
The circumference of a circle with radius r equals:
2\pi r
According to the graph, the radius of the circle is 4. Therefore, the circumference of this circle is:
2\times\pi \times 4 = 8\pi
The circumference of the circle is 8\pi.
Find the circumference of the circle with radius 5.
The circumference of a circle with radius r equals:
2\pi r
Therefore, the circumference of this circle is:
2\pi \times 5 = 10\pi
The circumference of the circle is 10\pi.
Find the area of the circle with radius 4.
The area of a circle with radius r equals:
\pi r^2
Therefore, the area of this circle is:
\pi \times 4^2 = 16\pi
The circumference of the circle is 16\pi.
Find the area of the following circle:
\left(x-1\right)^2+\left(y-\dfrac{1}{2}\right)^2=\dfrac{1}{4}
The area of a circle with radius r equals:
\pi r^2
The equation of a circle has the form:
\left(x-h\right)^2+\left(y-k\right)=r^2
So we have r=\dfrac{1}{2}.
Therefore, the area of this circle is:
\pi \times \left(\dfrac{1}{2}\right)^2 = \dfrac{1}{4}\pi
The circumference of the circle is \dfrac{1}{4}\pi.
Find the circumference of the circle with radius \dfrac{1}{2}.
The circumference of a circle with radius r equals:
2\pi r
Therefore, the circumference of this circle is:
2\pi \times \dfrac{1}{2} = \pi
The circumference of the circle is \pi.