Find circle given the center (4,9)\left(-4, 9\right), the diameter 1010

The calculator will find the equation of a circle and its properties given the center (4,9)\left(-4, 9\right), the diameter 1010, with steps shown.

Related calculator: Circle Calculator

Solution

The standard form of the equation of a circle is (xh)2+(yk)2=r2\left(x - h\right)^{2} + \left(y - k\right)^{2} = r^{2}, where (h,k)\left(h, k\right) is the center of the circle and rr is the radius.

Thus, h=4h = -4, k=9k = 9.

Since d=2rd = 2 r, then 2r=102 r = 10.

Solving the system {h=4k=92r=10\begin{cases} h = -4 \\ k = 9 \\ 2 r = 10 \end{cases}, we get that h=4h = -4, k=9k = 9, r=5r = 5 (for steps, see system of equations calculator).

The standard form is (x+4)2+(y9)2=25\left(x + 4\right)^{2} + \left(y - 9\right)^{2} = 25.

The general form can be found by moving everything to the left side and expanding (if needed): x2+8x+y218y+72=0x^{2} + 8 x + y^{2} - 18 y + 72 = 0.

Radius: r=5r = 5.

Area: A=πr2=25πA = \pi r^{2} = 25 \pi.

Both eccentricity and linear eccentricity of a circle equal 00.

The x-intercepts can be found by setting y=0y = 0 in the equation and solving for xx (for steps, see intercepts calculator).

Since there are no real solutions, there are no x-intercepts.

The y-intercepts can be found by setting x=0x = 0 in the equation and solving for yy: (for steps, see intercepts calculator).

y-intercepts: (0,6)\left(0, 6\right), (0,12)\left(0, 12\right)

The domain is [hr,h+r]=[9,1]\left[h - r, h + r\right] = \left[-9, 1\right].

The range is [kr,k+r]=[4,14]\left[k - r, k + r\right] = \left[4, 14\right].

Answer

Standard form/equation: (x+4)2+(y9)2=25\left(x + 4\right)^{2} + \left(y - 9\right)^{2} = 25A.

General form/equation: x2+8x+y218y+72=0x^{2} + 8 x + y^{2} - 18 y + 72 = 0A.

Graph: see the graphing calculator.

Center: (4,9)\left(-4, 9\right)A.

Radius: 55A.

Diameter: 1010A.

Circumference: 10π31.41592653589793210 \pi\approx 31.415926535897932A.

Area: 25π78.53981633974483125 \pi\approx 78.539816339744831A.

Eccentricity: 00A.

Linear eccentricity: 00A.

x-intercepts: no x-intercepts.

y-intercepts: (0,6)\left(0, 6\right), (0,12)\left(0, 12\right)A.

Domain: [9,1]\left[-9, 1\right]A.

Range: [4,14]\left[4, 14\right]A.